diff --git a/action.h b/action.h
index 27f1af9..c7fcba6 100644
--- a/action.h
+++ b/action.h
@@ -70,7 +70,7 @@
 // It is handy to have a non-templated base class of all Actions.
 class AbstractAction {
  public:
-  AbstractAction() : processor_(NULL) {}
+  AbstractAction() : processor_(nullptr) {}
 
   // Begin performing the action. Since this code is asynchronous, when this
   // method returns, it means only that the action has started, not necessarily
diff --git a/action_processor.cc b/action_processor.cc
index e3862c4..5e08a5f 100644
--- a/action_processor.cc
+++ b/action_processor.cc
@@ -12,7 +12,7 @@
 namespace chromeos_update_engine {
 
 ActionProcessor::ActionProcessor()
-    : current_action_(NULL), delegate_(NULL) {}
+    : current_action_(nullptr), delegate_(nullptr) {}
 
 ActionProcessor::~ActionProcessor() {
   if (IsRunning()) {
@@ -20,7 +20,7 @@
   }
   for (std::deque<AbstractAction*>::iterator it = actions_.begin();
        it != actions_.end(); ++it) {
-    (*it)->SetProcessor(NULL);
+    (*it)->SetProcessor(nullptr);
   }
 }
 
@@ -45,10 +45,10 @@
   CHECK(current_action_);
   current_action_->TerminateProcessing();
   CHECK(current_action_);
-  current_action_->SetProcessor(NULL);
+  current_action_->SetProcessor(nullptr);
   LOG(INFO) << "ActionProcessor::StopProcessing: aborted "
             << current_action_->Type();
-  current_action_ = NULL;
+  current_action_ = nullptr;
   if (delegate_)
     delegate_->ProcessingStopped(this);
 }
@@ -60,8 +60,8 @@
     delegate_->ActionCompleted(this, actionptr, code);
   string old_type = current_action_->Type();
   current_action_->ActionCompleted(code);
-  current_action_->SetProcessor(NULL);
-  current_action_ = NULL;
+  current_action_->SetProcessor(nullptr);
+  current_action_ = nullptr;
   if (actions_.empty()) {
     LOG(INFO) << "ActionProcessor::ActionComplete: finished last action of"
                  " type " << old_type;
diff --git a/action_processor.h b/action_processor.h
index adc4781..cb1aeb2 100644
--- a/action_processor.h
+++ b/action_processor.h
@@ -43,12 +43,12 @@
   void StopProcessing();
 
   // Returns true iff an Action is currently processing.
-  bool IsRunning() const { return NULL != current_action_; }
+  bool IsRunning() const { return nullptr != current_action_; }
 
   // Adds another Action to the end of the queue.
   virtual void EnqueueAction(AbstractAction* action);
 
-  // Sets/gets the current delegate. Set to NULL to remove a delegate.
+  // Sets/gets the current delegate. Set to null to remove a delegate.
   ActionProcessorDelegate* delegate() const { return delegate_; }
   void set_delegate(ActionProcessorDelegate *delegate) {
     delegate_ = delegate;
@@ -70,7 +70,7 @@
   // A pointer to the currently processing Action, if any.
   AbstractAction* current_action_;
 
-  // A pointer to the delegate, or NULL if none.
+  // A pointer to the delegate, or null if none.
   ActionProcessorDelegate *delegate_;
   DISALLOW_COPY_AND_ASSIGN(ActionProcessor);
 };
diff --git a/action_processor_unittest.cc b/action_processor_unittest.cc
index 78968ef..cde1eec 100644
--- a/action_processor_unittest.cc
+++ b/action_processor_unittest.cc
@@ -105,7 +105,7 @@
   action_processor.EnqueueAction(&action);
   action_processor.StartProcessing();
   action.CompleteAction();
-  action_processor.set_delegate(NULL);
+  action_processor.set_delegate(nullptr);
   EXPECT_TRUE(delegate.processing_done_called_);
   EXPECT_TRUE(delegate.action_completed_called_);
 }
@@ -119,11 +119,11 @@
   action_processor.EnqueueAction(&action);
   action_processor.StartProcessing();
   action_processor.StopProcessing();
-  action_processor.set_delegate(NULL);
+  action_processor.set_delegate(nullptr);
   EXPECT_TRUE(delegate.processing_stopped_called_);
   EXPECT_FALSE(delegate.action_completed_called_);
   EXPECT_FALSE(action_processor.IsRunning());
-  EXPECT_EQ(NULL, action_processor.current_action());
+  EXPECT_EQ(nullptr, action_processor.current_action());
 }
 
 TEST(ActionProcessorTest, ChainActionsTest) {
@@ -138,7 +138,7 @@
   EXPECT_EQ(&action2, action_processor.current_action());
   EXPECT_TRUE(action_processor.IsRunning());
   action2.CompleteAction();
-  EXPECT_EQ(NULL, action_processor.current_action());
+  EXPECT_EQ(nullptr, action_processor.current_action());
   EXPECT_FALSE(action_processor.IsRunning());
 }
 
@@ -150,9 +150,9 @@
     action_processor.EnqueueAction(&action2);
     action_processor.StartProcessing();
   }
-  EXPECT_EQ(NULL, action1.processor());
+  EXPECT_EQ(nullptr, action1.processor());
   EXPECT_FALSE(action1.IsRunning());
-  EXPECT_EQ(NULL, action2.processor());
+  EXPECT_EQ(nullptr, action2.processor());
   EXPECT_FALSE(action2.IsRunning());
 }
 
@@ -171,7 +171,7 @@
   action_processor.StartProcessing();
   action_processor.StopProcessing();
 
-  action_processor.set_delegate(NULL);
+  action_processor.set_delegate(nullptr);
 }
 
 }  // namespace chromeos_update_engine
diff --git a/bzip_extent_writer_unittest.cc b/bzip_extent_writer_unittest.cc
index 185c201..fb4d90b 100644
--- a/bzip_extent_writer_unittest.cc
+++ b/bzip_extent_writer_unittest.cc
@@ -77,10 +77,10 @@
   const vector<char>::size_type kDecompressedLength = 2048 * 1024;  // 2 MiB
   string decompressed_path;
   ASSERT_TRUE(utils::MakeTempFile("BzipExtentWriterTest-decompressed-XXXXXX",
-                                  &decompressed_path, NULL));
+                                  &decompressed_path, nullptr));
   string compressed_path;
   ASSERT_TRUE(utils::MakeTempFile("BzipExtentWriterTest-compressed-XXXXXX",
-                                  &compressed_path, NULL));
+                                  &compressed_path, nullptr));
   const size_t kChunkSize = 3;
 
   vector<Extent> extents;
diff --git a/certificate_checker.cc b/certificate_checker.cc
index a774900..4dd9182 100644
--- a/certificate_checker.cc
+++ b/certificate_checker.cc
@@ -52,10 +52,10 @@
 }
 
 // static
-SystemState* CertificateChecker::system_state_ = NULL;
+SystemState* CertificateChecker::system_state_ = nullptr;
 
 // static
-OpenSSLWrapper* CertificateChecker::openssl_wrapper_ = NULL;
+OpenSSLWrapper* CertificateChecker::openssl_wrapper_ = nullptr;
 
 // static
 CURLcode CertificateChecker::ProcessSSLContext(CURL* curl_handle,
@@ -103,8 +103,8 @@
   static const char kUMAActionCertChanged[] =
       "Updater.ServerCertificateChanged";
   static const char kUMAActionCertFailed[] = "Updater.ServerCertificateFailed";
-  TEST_AND_RETURN_FALSE(system_state_ != NULL);
-  TEST_AND_RETURN_FALSE(system_state_->prefs() != NULL);
+  TEST_AND_RETURN_FALSE(system_state_ != nullptr);
+  TEST_AND_RETURN_FALSE(system_state_->prefs() != nullptr);
   TEST_AND_RETURN_FALSE(server_to_check != kNone);
 
   // If pre-verification failed, we are not interested in the current
diff --git a/certificate_checker_unittest.cc b/certificate_checker_unittest.cc
index 4469c0f..ef9bbd2 100644
--- a/certificate_checker_unittest.cc
+++ b/certificate_checker_unittest.cc
@@ -72,7 +72,7 @@
 
 // check certificate change, new
 TEST_F(CertificateCheckerTest, NewCertificate) {
-  EXPECT_CALL(openssl_wrapper_, GetCertificateDigest(NULL, _, _, _))
+  EXPECT_CALL(openssl_wrapper_, GetCertificateDigest(nullptr, _, _, _))
       .WillOnce(DoAll(
           SetArgumentPointee<1>(depth_),
           SetArgumentPointee<2>(length_),
@@ -83,12 +83,12 @@
   EXPECT_CALL(*prefs_, SetString(cert_key_, digest_hex_))
       .WillOnce(Return(true));
   ASSERT_TRUE(CertificateChecker::CheckCertificateChange(
-      server_to_check_, 1, NULL));
+      server_to_check_, 1, nullptr));
 }
 
 // check certificate change, unchanged
 TEST_F(CertificateCheckerTest, SameCertificate) {
-  EXPECT_CALL(openssl_wrapper_, GetCertificateDigest(NULL, _, _, _))
+  EXPECT_CALL(openssl_wrapper_, GetCertificateDigest(nullptr, _, _, _))
       .WillOnce(DoAll(
           SetArgumentPointee<1>(depth_),
           SetArgumentPointee<2>(length_),
@@ -100,12 +100,12 @@
           Return(true)));
   EXPECT_CALL(*prefs_, SetString(_, _)).Times(0);
   ASSERT_TRUE(CertificateChecker::CheckCertificateChange(
-      server_to_check_, 1, NULL));
+      server_to_check_, 1, nullptr));
 }
 
 // check certificate change, changed
 TEST_F(CertificateCheckerTest, ChangedCertificate) {
-  EXPECT_CALL(openssl_wrapper_, GetCertificateDigest(NULL, _, _, _))
+  EXPECT_CALL(openssl_wrapper_, GetCertificateDigest(nullptr, _, _, _))
       .WillOnce(DoAll(
           SetArgumentPointee<1>(depth_),
           SetArgumentPointee<2>(length_),
@@ -121,7 +121,7 @@
   EXPECT_CALL(*prefs_, SetString(cert_key_, digest_hex_))
       .WillOnce(Return(true));
   ASSERT_TRUE(CertificateChecker::CheckCertificateChange(
-      server_to_check_, 1, NULL));
+      server_to_check_, 1, nullptr));
 }
 
 // check certificate change, failed
@@ -132,7 +132,7 @@
   EXPECT_CALL(*prefs_, GetString(_, _)).Times(0);
   EXPECT_CALL(openssl_wrapper_, GetCertificateDigest(_, _, _, _)).Times(0);
   ASSERT_FALSE(CertificateChecker::CheckCertificateChange(
-      server_to_check_, 0, NULL));
+      server_to_check_, 0, nullptr));
 }
 
 // flush send report
diff --git a/chrome_browser_proxy_resolver.cc b/chrome_browser_proxy_resolver.cc
index 4ee1679..85646f8 100644
--- a/chrome_browser_proxy_resolver.cc
+++ b/chrome_browser_proxy_resolver.cc
@@ -53,14 +53,14 @@
 
 ChromeBrowserProxyResolver::ChromeBrowserProxyResolver(
     DBusWrapperInterface* dbus)
-    : dbus_(dbus), proxy_(NULL), timeout_(kTimeout) {}
+    : dbus_(dbus), proxy_(nullptr), timeout_(kTimeout) {}
 
 bool ChromeBrowserProxyResolver::Init() {
   if (proxy_)
     return true;  // Already initialized.
 
   // Set up signal handler. Code lifted from libcros.
-  GError* g_error = NULL;
+  GError* g_error = nullptr;
   DBusGConnection* bus = dbus_->BusGet(DBUS_BUS_SYSTEM, &g_error);
   TEST_AND_RETURN_FALSE(bus);
   DBusConnection* connection = dbus_->ConnectionGetConnection(bus);
@@ -75,7 +75,7 @@
       connection,
       &ChromeBrowserProxyResolver::StaticFilterMessage,
       this,
-      NULL));
+      nullptr));
 
   proxy_ = dbus_->ProxyNewForName(bus, kLibCrosServiceName, kLibCrosServicePath,
                                   kLibCrosServiceInterface);
@@ -92,7 +92,7 @@
 ChromeBrowserProxyResolver::~ChromeBrowserProxyResolver() {
   // Remove DBus connection filters and Kill proxy object.
   if (proxy_) {
-    GError* gerror = NULL;
+    GError* gerror = nullptr;
     DBusGConnection* gbus = dbus_->BusGet(DBUS_BUS_SYSTEM, &gerror);
     if (gbus) {
       DBusConnection* connection = dbus_->ConnectionGetConnection(gbus);
@@ -108,14 +108,14 @@
   for (TimeoutsMap::iterator it = timers_.begin(), e = timers_.end(); it != e;
        ++it) {
     g_source_destroy(it->second);
-    it->second = NULL;
+    it->second = nullptr;
   }
 }
 
 bool ChromeBrowserProxyResolver::GetProxiesForUrl(const string& url,
                                                   ProxiesResolvedFn callback,
                                                   void* data) {
-  GError* error = NULL;
+  GError* error = nullptr;
   guint timeout = timeout_;
   if (proxy_) {
     if (!dbus_->ProxyCall_3_0(proxy_,
@@ -146,7 +146,7 @@
   GSource* timer = g_timeout_source_new_seconds(timeout);
   g_source_set_callback(
       timer, utils::GlibRunClosure, closure, utils::GlibDestroyClosure);
-  g_source_attach(timer, NULL);
+  g_source_attach(timer, nullptr);
   timers_.insert(make_pair(url, timer));
   return true;
 }
@@ -161,9 +161,9 @@
     return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
   }
   // Get args
-  char* source_url = NULL;
-  char* proxy_list = NULL;
-  char* error = NULL;
+  char* source_url = nullptr;
+  char* proxy_list = nullptr;
+  char* error = nullptr;
   DBusError arg_error;
   dbus_error_init(&arg_error);
   if (!dbus_->DBusMessageGetArgs_3(message, &arg_error,
diff --git a/connection_manager.cc b/connection_manager.cc
index b5daa14..f6c0217 100644
--- a/connection_manager.cc
+++ b/connection_manager.cc
@@ -32,7 +32,7 @@
                       DBusGProxy** out_proxy) {
   DBusGConnection* bus;
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   bus = dbus_iface->BusGet(DBUS_BUS_SYSTEM, &error);
   if (!bus) {
@@ -52,7 +52,7 @@
                    const char* interface,
                    GHashTable** out_hash_table) {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   TEST_AND_RETURN_FALSE(GetFlimFlamProxy(dbus_iface,
                                          path,
@@ -76,7 +76,7 @@
 // there's no network up.
 // Returns true on success.
 bool GetDefaultServicePath(DBusWrapperInterface* dbus_iface, string* out_path) {
-  GHashTable* hash_table = NULL;
+  GHashTable* hash_table = nullptr;
 
   TEST_AND_RETURN_FALSE(GetProperties(dbus_iface,
                                       shill::kFlimflamServicePath,
@@ -85,7 +85,7 @@
 
   GValue* value = reinterpret_cast<GValue*>(g_hash_table_lookup(hash_table,
                                                                 "Services"));
-  GPtrArray* array = NULL;
+  GPtrArray* array = nullptr;
   bool success = false;
   if (G_VALUE_HOLDS(value, DBUS_TYPE_G_OBJECT_PATH_ARRAY) &&
       (array = reinterpret_cast<GPtrArray*>(g_value_get_boxed(value))) &&
@@ -129,7 +129,7 @@
                               const string& path,
                               NetworkConnectionType* out_type,
                               NetworkTethering* out_tethering) {
-  GHashTable* hash_table = NULL;
+  GHashTable* hash_table = nullptr;
 
   TEST_AND_RETURN_FALSE(GetProperties(dbus_iface,
                                       path.c_str(),
@@ -140,11 +140,11 @@
   GValue* value =
       reinterpret_cast<GValue*>(g_hash_table_lookup(hash_table,
                                                     shill::kTetheringProperty));
-  const char* tethering_str = NULL;
+  const char* tethering_str = nullptr;
 
-  if (value != NULL)
+  if (value != nullptr)
     tethering_str = g_value_get_string(value);
-  if (tethering_str != NULL) {
+  if (tethering_str != nullptr) {
     *out_tethering = ParseTethering(tethering_str);
   } else {
     // Set to Unknown if not present.
@@ -154,14 +154,15 @@
   // Populate the out_type property.
   value = reinterpret_cast<GValue*>(g_hash_table_lookup(hash_table,
                                                         shill::kTypeProperty));
-  const char* type_str = NULL;
+  const char* type_str = nullptr;
   bool success = false;
-  if (value != NULL && (type_str = g_value_get_string(value)) != NULL) {
+  if (value != nullptr && (type_str = g_value_get_string(value)) != nullptr) {
     success = true;
     if (!strcmp(type_str, shill::kTypeVPN)) {
       value = reinterpret_cast<GValue*>(
           g_hash_table_lookup(hash_table, shill::kPhysicalTechnologyProperty));
-      if (value != NULL && (type_str = g_value_get_string(value)) != NULL) {
+      if (value != nullptr &&
+          (type_str = g_value_get_string(value)) != nullptr) {
         *out_type = ParseConnectionType(type_str);
       } else {
         LOG(ERROR) << "No PhysicalTechnology property found for a VPN"
diff --git a/connection_manager_unittest.cc b/connection_manager_unittest.cc
index ca6e256..47adf11 100644
--- a/connection_manager_unittest.cc
+++ b/connection_manager_unittest.cc
@@ -28,9 +28,9 @@
 class ConnectionManagerTest : public ::testing::Test {
  public:
   ConnectionManagerTest()
-      : kMockFlimFlamManagerProxy_(NULL),
-        kMockFlimFlamServiceProxy_(NULL),
-        kServicePath_(NULL),
+      : kMockFlimFlamManagerProxy_(nullptr),
+        kMockFlimFlamServiceProxy_(nullptr),
+        kServicePath_(nullptr),
         cmut_(&fake_system_state_) {
     fake_system_state_.set_connection_manager(&cmut_);
   }
@@ -40,7 +40,7 @@
   void SetManagerReply(const char* reply_value, const GType& reply_type);
 
   // Sets the |service_type| Type and the |physical_technology|
-  // PhysicalTechnology properties in the mocked service. If a NULL
+  // PhysicalTechnology properties in the mocked service. If a null
   // |physical_technology| is passed, the property is not set (not present).
   void SetServiceReply(const char* service_type,
                        const char* physical_technology,
@@ -71,7 +71,7 @@
   kMockSystemBus_ = reinterpret_cast<DBusGConnection*>(number++);
   kMockFlimFlamManagerProxy_ = reinterpret_cast<DBusGProxy*>(number++);
   kMockFlimFlamServiceProxy_ = reinterpret_cast<DBusGProxy*>(number++);
-  ASSERT_NE(kMockSystemBus_, reinterpret_cast<DBusGConnection*>(NULL));
+  ASSERT_NE(kMockSystemBus_, static_cast<DBusGConnection*>(nullptr));
 
   kServicePath_ = service_path;
 
@@ -91,7 +91,7 @@
   // of the GPtrArray automatically when the |array_as_value| GValue is unset.
   // The g_strdup() is not being leaked.
   GPtrArray* array = g_ptr_array_new();
-  ASSERT_TRUE(array != NULL);
+  ASSERT_NE(nullptr, array);
   g_ptr_array_add(array, g_strdup(reply_value));
 
   GValue* array_as_value = g_new0(GValue, 1);
@@ -140,14 +140,14 @@
                       const_cast<char*>("Type"),
                       service_type_value);
 
-  if (physical_technology != NULL) {
+  if (physical_technology) {
     GValue* physical_technology_value = GValueNewString(physical_technology);
     g_hash_table_insert(service_hash_table,
                         const_cast<char*>("PhysicalTechnology"),
                         physical_technology_value);
   }
 
-  if (service_tethering != NULL) {
+  if (service_tethering) {
     GValue* service_tethering_value = GValueNewString(service_tethering);
     g_hash_table_insert(service_hash_table,
                         const_cast<char*>("Tethering"),
@@ -195,7 +195,7 @@
 
   SetupMocks("/service/guest-network");
   SetManagerReply(kServicePath_, DBUS_TYPE_G_OBJECT_PATH_ARRAY);
-  SetServiceReply(shill::kTypeWifi, NULL, service_tethering);
+  SetServiceReply(shill::kTypeWifi, nullptr, service_tethering);
 
   NetworkConnectionType type;
   NetworkTethering tethering;
@@ -204,15 +204,15 @@
 }
 
 TEST_F(ConnectionManagerTest, SimpleTest) {
-  TestWithServiceType(shill::kTypeEthernet, NULL, kNetEthernet);
-  TestWithServiceType(shill::kTypeWifi, NULL, kNetWifi);
-  TestWithServiceType(shill::kTypeWimax, NULL, kNetWimax);
-  TestWithServiceType(shill::kTypeBluetooth, NULL, kNetBluetooth);
-  TestWithServiceType(shill::kTypeCellular, NULL, kNetCellular);
+  TestWithServiceType(shill::kTypeEthernet, nullptr, kNetEthernet);
+  TestWithServiceType(shill::kTypeWifi, nullptr, kNetWifi);
+  TestWithServiceType(shill::kTypeWimax, nullptr, kNetWimax);
+  TestWithServiceType(shill::kTypeBluetooth, nullptr, kNetBluetooth);
+  TestWithServiceType(shill::kTypeCellular, nullptr, kNetCellular);
 }
 
 TEST_F(ConnectionManagerTest, PhysicalTechnologyTest) {
-  TestWithServiceType(shill::kTypeVPN, NULL, kNetUnknown);
+  TestWithServiceType(shill::kTypeVPN, nullptr, kNetUnknown);
   TestWithServiceType(shill::kTypeVPN, shill::kTypeVPN, kNetUnknown);
   TestWithServiceType(shill::kTypeVPN, shill::kTypeWifi, kNetWifi);
   TestWithServiceType(shill::kTypeVPN, shill::kTypeWimax, kNetWimax);
@@ -230,7 +230,7 @@
 }
 
 TEST_F(ConnectionManagerTest, UnknownTest) {
-  TestWithServiceType("foo", NULL, kNetUnknown);
+  TestWithServiceType("foo", nullptr, kNetUnknown);
 }
 
 TEST_F(ConnectionManagerTest, AllowUpdatesOverEthernetTest) {
diff --git a/dbus_service.cc b/dbus_service.cc
index a8e1dcd..36ee494 100644
--- a/dbus_service.cc
+++ b/dbus_service.cc
@@ -97,9 +97,9 @@
       G_OBJECT_CLASS_TYPE(klass),
       G_SIGNAL_RUN_LAST,
       0,  // 0 == no class method associated
-      NULL,  // Accumulator
-      NULL,  // Accumulator data
-      NULL,  // Marshaller
+      nullptr,  // Accumulator
+      nullptr,  // Accumulator data
+      nullptr,  // Marshaller
       G_TYPE_NONE,  // Return type
       5,  // param count:
       G_TYPE_INT64,
@@ -117,7 +117,7 @@
 
 UpdateEngineService* update_engine_service_new(void) {
   return reinterpret_cast<UpdateEngineService*>(
-      g_object_new(UPDATE_ENGINE_TYPE_SERVICE, NULL));
+      g_object_new(UPDATE_ENGINE_TYPE_SERVICE, nullptr));
 }
 
 gboolean update_engine_service_attempt_update(UpdateEngineService* self,
diff --git a/delta_performer.cc b/delta_performer.cc
index a22adfb..ce44be5 100644
--- a/delta_performer.cc
+++ b/delta_performer.cc
@@ -594,7 +594,7 @@
 
   // Since bzip decompression is optional, we have a variable writer that will
   // point to one of the ExtentWriter objects above.
-  ExtentWriter* writer = NULL;
+  ExtentWriter* writer = nullptr;
   if (operation.type() == DeltaArchiveManifest_InstallOperation_Type_REPLACE) {
     writer = &zero_pad_writer;
   } else if (operation.type() ==
@@ -744,7 +744,7 @@
   string temp_filename;
   TEST_AND_RETURN_FALSE(utils::MakeTempFile("/tmp/au_patch.XXXXXX",
                                             &temp_filename,
-                                            NULL));
+                                            nullptr));
   ScopedPathUnlinker path_unlinker(temp_filename);
   {
     int fd = open(temp_filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0644);
@@ -780,7 +780,7 @@
       Subprocess::SynchronousExecFlags(cmd,
                                        G_SPAWN_LEAVE_DESCRIPTORS_OPEN,
                                        &return_code,
-                                       NULL));
+                                       nullptr));
   TEST_AND_RETURN_FALSE(return_code == 0);
 
   if (operation.dst_length() % block_size_) {
diff --git a/delta_performer_unittest.cc b/delta_performer_unittest.cc
index d68aa25..8b640e8 100644
--- a/delta_performer_unittest.cc
+++ b/delta_performer_unittest.cc
@@ -185,7 +185,7 @@
   if (signature_test == kSignatureGeneratedShellBadKey) {
     ASSERT_TRUE(utils::MakeTempFile("key.XXXXXX",
                                     &private_key_path,
-                                    NULL));
+                                    nullptr));
   } else {
     ASSERT_TRUE(signature_test == kSignatureGeneratedShell ||
                 signature_test == kSignatureGeneratedShellRotateCl1 ||
@@ -203,7 +203,7 @@
   }
   int signature_size = GetSignatureSize(private_key_path);
   string hash_file;
-  ASSERT_TRUE(utils::MakeTempFile("hash.XXXXXX", &hash_file, NULL));
+  ASSERT_TRUE(utils::MakeTempFile("hash.XXXXXX", &hash_file, nullptr));
   ScopedPathUnlinker hash_unlinker(hash_file);
   string signature_size_string;
   if (signature_test == kSignatureGeneratedShellRotateCl1 ||
@@ -227,7 +227,7 @@
   ASSERT_TRUE(WriteFileVector(hash_file, hash));
 
   string sig_file;
-  ASSERT_TRUE(utils::MakeTempFile("signature.XXXXXX", &sig_file, NULL));
+  ASSERT_TRUE(utils::MakeTempFile("signature.XXXXXX", &sig_file, nullptr));
   ScopedPathUnlinker sig_unlinker(sig_file);
   ASSERT_EQ(0,
             System(base::StringPrintf(
@@ -237,7 +237,7 @@
                 hash_file.c_str(),
                 sig_file.c_str())));
   string sig_file2;
-  ASSERT_TRUE(utils::MakeTempFile("signature.XXXXXX", &sig_file2, NULL));
+  ASSERT_TRUE(utils::MakeTempFile("signature.XXXXXX", &sig_file2, nullptr));
   ScopedPathUnlinker sig2_unlinker(sig_file2);
   if (signature_test == kSignatureGeneratedShellRotateCl1 ||
       signature_test == kSignatureGeneratedShellRotateCl2) {
@@ -279,9 +279,9 @@
                               off_t chunk_size,
                               SignatureTest signature_test,
                               DeltaState *state) {
-  EXPECT_TRUE(utils::MakeTempFile("a_img.XXXXXX", &state->a_img, NULL));
-  EXPECT_TRUE(utils::MakeTempFile("b_img.XXXXXX", &state->b_img, NULL));
-  CreateExtImageAtPath(state->a_img, NULL);
+  EXPECT_TRUE(utils::MakeTempFile("a_img.XXXXXX", &state->a_img, nullptr));
+  EXPECT_TRUE(utils::MakeTempFile("b_img.XXXXXX", &state->b_img, nullptr));
+  CreateExtImageAtPath(state->a_img, nullptr);
 
   state->image_size = static_cast<int>(utils::FileSize(state->a_img));
 
@@ -357,7 +357,7 @@
                                base::FilePath(state->b_img)));
     old_image_info = new_image_info;
   } else {
-    CreateExtImageAtPath(state->b_img, NULL);
+    CreateExtImageAtPath(state->b_img, nullptr);
     EXPECT_EQ(0, System(base::StringPrintf(
         "dd if=/dev/zero of=%s seek=%d bs=1 count=1",
         state->b_img.c_str(),
@@ -428,12 +428,12 @@
   string old_kernel;
   EXPECT_TRUE(utils::MakeTempFile("old_kernel.XXXXXX",
                                   &state->old_kernel,
-                                  NULL));
+                                  nullptr));
 
   string new_kernel;
   EXPECT_TRUE(utils::MakeTempFile("new_kernel.XXXXXX",
                                   &state->new_kernel,
-                                  NULL));
+                                  nullptr));
 
   state->old_kernel_data.resize(kDefaultKernelSize);
   state->new_kernel_data.resize(state->old_kernel_data.size());
@@ -457,7 +457,7 @@
 
   EXPECT_TRUE(utils::MakeTempFile("delta.XXXXXX",
                                   &state->delta_path,
-                                  NULL));
+                                  nullptr));
   LOG(INFO) << "delta path: " << state->delta_path;
   {
     string a_mnt, b_mnt;
@@ -477,7 +477,7 @@
             private_key,
             chunk_size,
             kRootFSPartitionSize,
-            full_rootfs ? NULL : &old_image_info,
+            full_rootfs ? nullptr : &old_image_info,
             &new_image_info,
             &state->metadata_size));
   }
@@ -732,7 +732,7 @@
                          DeltaState* state,
                          ErrorCode expected_result) {
   if (!performer) {
-    EXPECT_TRUE(!"Skipping payload verification since performer is NULL.");
+    EXPECT_TRUE(!"Skipping payload verification since performer is null.");
     return;
   }
 
diff --git a/download_action.cc b/download_action.cc
index 0d4354b..5b3ffeb 100644
--- a/download_action.cc
+++ b/download_action.cc
@@ -32,9 +32,9 @@
     : prefs_(prefs),
       system_state_(system_state),
       http_fetcher_(http_fetcher),
-      writer_(NULL),
+      writer_(nullptr),
       code_(ErrorCode::kSuccess),
-      delegate_(NULL),
+      delegate_(nullptr),
       bytes_received_(0),
       p2p_sharing_fd_(-1),
       p2p_visible_(true) {}
@@ -188,7 +188,7 @@
     delegate_->SetDownloadStatus(true);  // Set to active.
   }
 
-  if (system_state_ != NULL) {
+  if (system_state_ != nullptr) {
     string file_id = utils::CalculateP2PFileId(install_plan_.payload_hash,
                                                install_plan_.payload_size);
     if (system_state_->request_params()->use_p2p_for_sharing()) {
@@ -216,7 +216,7 @@
 
   // Tweak timeouts on the HTTP fetcher if we're downloading from a
   // local peer.
-  if (system_state_ != NULL &&
+  if (system_state_ != nullptr &&
       system_state_->request_params()->use_p2p_for_downloading() &&
       system_state_->request_params()->p2p_url() ==
       install_plan_.download_url) {
@@ -233,7 +233,7 @@
 void DownloadAction::TerminateProcessing() {
   if (writer_) {
     writer_->Close();
-    writer_ = NULL;
+    writer_ = nullptr;
   }
   if (delegate_) {
     delegate_->SetDownloadStatus(false);  // Set to inactive.
@@ -285,7 +285,7 @@
 void DownloadAction::TransferComplete(HttpFetcher *fetcher, bool successful) {
   if (writer_) {
     LOG_IF(WARNING, writer_->Close() != 0) << "Error closing the writer.";
-    writer_ = NULL;
+    writer_ = nullptr;
   }
   if (delegate_) {
     delegate_->SetDownloadStatus(false);  // Set to inactive.
diff --git a/download_action_unittest.cc b/download_action_unittest.cc
index e061782..97dd0f3 100644
--- a/download_action_unittest.cc
+++ b/download_action_unittest.cc
@@ -48,7 +48,7 @@
 class DownloadActionTestProcessorDelegate : public ActionProcessorDelegate {
  public:
   explicit DownloadActionTestProcessorDelegate(ErrorCode expected_code)
-      : loop_(NULL),
+      : loop_(nullptr),
         processing_done_called_(false),
         expected_code_(expected_code) {}
   virtual ~DownloadActionTestProcessorDelegate() {
@@ -156,9 +156,9 @@
   PrefsMock prefs;
   MockHttpFetcher* http_fetcher = new MockHttpFetcher(&data[0],
                                                       data.size(),
-                                                      NULL);
+                                                      nullptr);
   // takes ownership of passed in HttpFetcher
-  DownloadAction download_action(&prefs, NULL, http_fetcher);
+  DownloadAction download_action(&prefs, nullptr, http_fetcher);
   download_action.SetTestFileWriter(&writer);
   BondActions(&feeder_action, &download_action);
   DownloadActionDelegateMock download_delegate;
@@ -269,10 +269,10 @@
                              temp_file.GetPath(), "", "");
     feeder_action.set_obj(install_plan);
     PrefsMock prefs;
-    DownloadAction download_action(&prefs, NULL,
+    DownloadAction download_action(&prefs, nullptr,
                                    new MockHttpFetcher(&data[0],
                                                        data.size(),
-                                                       NULL));
+                                                       nullptr));
     download_action.SetTestFileWriter(&writer);
     DownloadActionDelegateMock download_delegate;
     if (use_download_delegate) {
@@ -380,8 +380,8 @@
   ObjectFeederAction<InstallPlan> feeder_action;
   feeder_action.set_obj(install_plan);
   PrefsMock prefs;
-  DownloadAction download_action(&prefs, NULL,
-                                 new MockHttpFetcher("x", 1, NULL));
+  DownloadAction download_action(&prefs, nullptr,
+                                 new MockHttpFetcher("x", 1, nullptr));
   download_action.SetTestFileWriter(&writer);
 
   DownloadActionTestAction test_action;
@@ -415,8 +415,8 @@
   ObjectFeederAction<InstallPlan> feeder_action;
   feeder_action.set_obj(install_plan);
   PrefsMock prefs;
-  DownloadAction download_action(&prefs, NULL,
-                                 new MockHttpFetcher("x", 1, NULL));
+  DownloadAction download_action(&prefs, nullptr,
+                                 new MockHttpFetcher("x", 1, nullptr));
   download_action.SetTestFileWriter(&writer);
 
   BondActions(&feeder_action, &download_action);
@@ -440,7 +440,7 @@
 class P2PDownloadActionTest : public testing::Test {
  protected:
   P2PDownloadActionTest()
-    : loop_(NULL),
+    : loop_(nullptr),
       start_at_offset_(0) {}
 
   virtual ~P2PDownloadActionTest() {}
@@ -452,7 +452,7 @@
 
   // Derived from testing::Test.
   virtual void TearDown() {
-    if (loop_ != NULL)
+    if (loop_ != nullptr)
       g_main_loop_unref(loop_);
   }
 
@@ -467,7 +467,7 @@
 
     // Setup p2p.
     FakeP2PManagerConfiguration *test_conf = new FakeP2PManagerConfiguration();
-    p2p_manager_.reset(P2PManager::Construct(test_conf, NULL, "cros_au", 3));
+    p2p_manager_.reset(P2PManager::Construct(test_conf, nullptr, "cros_au", 3));
     fake_system_state_.set_p2p_manager(p2p_manager_.get());
   }
 
@@ -495,7 +495,7 @@
     PrefsMock prefs;
     http_fetcher_ = new MockHttpFetcher(data_.c_str(),
                                         data_.length(),
-                                        NULL);
+                                        nullptr);
     // Note that DownloadAction takes ownership of the passed in HttpFetcher.
     download_action_.reset(new DownloadAction(&prefs, &fake_system_state_,
                                               http_fetcher_));
diff --git a/extent_writer_unittest.cc b/extent_writer_unittest.cc
index fcd57dd..fef3343 100644
--- a/extent_writer_unittest.cc
+++ b/extent_writer_unittest.cc
@@ -92,7 +92,7 @@
 
   DirectExtentWriter direct_writer;
   EXPECT_TRUE(direct_writer.Init(fd(), extents, kBlockSize));
-  EXPECT_TRUE(direct_writer.Write(NULL, 0));
+  EXPECT_TRUE(direct_writer.Write(nullptr, 0));
   EXPECT_TRUE(direct_writer.End());
 }
 
diff --git a/fake_p2p_manager_configuration.h b/fake_p2p_manager_configuration.h
index 8756630..0645d7a 100644
--- a/fake_p2p_manager_configuration.h
+++ b/fake_p2p_manager_configuration.h
@@ -98,7 +98,7 @@
     if (!g_shell_parse_argv(command_line.c_str(),
                             &argc,
                             &argv,
-                            NULL)) {
+                            nullptr)) {
       LOG(ERROR) << "Error splitting '" << command_line << "'";
       return ret;
     }
diff --git a/fake_prefs.cc b/fake_prefs.cc
index e26b865..653104e 100644
--- a/fake_prefs.cc
+++ b/fake_prefs.cc
@@ -15,7 +15,7 @@
 
 void CheckNotNull(const string& key, void* ptr) {
   EXPECT_NE(nullptr, ptr)
-      << "Called Get*() for key \"" << key << "\" with a NULL parameter.";
+      << "Called Get*() for key \"" << key << "\" with a null parameter.";
 }
 
 }  // namespace
diff --git a/file_writer_unittest.cc b/file_writer_unittest.cc
index 5d24eab..8f4ab9e 100644
--- a/file_writer_unittest.cc
+++ b/file_writer_unittest.cc
@@ -26,7 +26,7 @@
 TEST(FileWriterTest, SimpleTest) {
   // Create a uniquely named file for testing.
   string path;
-  ASSERT_TRUE(utils::MakeTempFile("FileWriterTest-XXXXXX", &path, NULL));
+  ASSERT_TRUE(utils::MakeTempFile("FileWriterTest-XXXXXX", &path, nullptr));
   ScopedPathUnlinker path_unlinker(path);
 
   DirectFileWriter file_writer;
@@ -51,7 +51,7 @@
 TEST(FileWriterTest, WriteErrorTest) {
   // Create a uniquely named file for testing.
   string path;
-  ASSERT_TRUE(utils::MakeTempFile("FileWriterTest-XXXXXX", &path, NULL));
+  ASSERT_TRUE(utils::MakeTempFile("FileWriterTest-XXXXXX", &path, nullptr));
   ScopedPathUnlinker path_unlinker(path);
 
   DirectFileWriter file_writer;
diff --git a/filesystem_copier_action.cc b/filesystem_copier_action.cc
index efd454d..a8f56e9 100644
--- a/filesystem_copier_action.cc
+++ b/filesystem_copier_action.cc
@@ -43,8 +43,8 @@
     bool verify_hash)
     : copying_kernel_install_path_(copying_kernel_install_path),
       verify_hash_(verify_hash),
-      src_stream_(NULL),
-      dst_stream_(NULL),
+      src_stream_(nullptr),
+      dst_stream_(nullptr),
       read_done_(false),
       failed_(false),
       cancelled_(false),
@@ -60,7 +60,7 @@
   for (int i = 0; i < 2; ++i) {
     buffer_state_[i] = kBufferStateEmpty;
     buffer_valid_size_[i] = 0;
-    canceller_[i] = NULL;
+    canceller_[i] = nullptr;
   }
 }
 
@@ -154,19 +154,19 @@
 }
 
 bool FilesystemCopierAction::IsCleanupPending() const {
-  return (src_stream_ != NULL);
+  return (src_stream_ != nullptr);
 }
 
 void FilesystemCopierAction::Cleanup(ErrorCode code) {
   for (int i = 0; i < 2; i++) {
     g_object_unref(canceller_[i]);
-    canceller_[i] = NULL;
+    canceller_[i] = nullptr;
   }
   g_object_unref(src_stream_);
-  src_stream_ = NULL;
+  src_stream_ = nullptr;
   if (dst_stream_) {
     g_object_unref(dst_stream_);
-    dst_stream_ = NULL;
+    dst_stream_ = nullptr;
   }
   if (cancelled_)
     return;
@@ -180,7 +180,7 @@
   int index = buffer_state_[0] == kBufferStateReading ? 0 : 1;
   CHECK(buffer_state_[index] == kBufferStateReading);
 
-  GError* error = NULL;
+  GError* error = nullptr;
   CHECK(canceller_[index]);
   cancelled_ = g_cancellable_is_cancelled(canceller_[index]) == TRUE;
 
@@ -227,7 +227,7 @@
   CHECK(buffer_state_[index] == kBufferStateWriting);
   buffer_state_[index] = kBufferStateEmpty;
 
-  GError* error = NULL;
+  GError* error = nullptr;
   CHECK(canceller_[index]);
   cancelled_ = g_cancellable_is_cancelled(canceller_[index]) == TRUE;
 
diff --git a/filesystem_copier_action.h b/filesystem_copier_action.h
index cdb3d8b..4ebe905 100644
--- a/filesystem_copier_action.h
+++ b/filesystem_copier_action.h
@@ -100,7 +100,7 @@
   // passed in InstallPlan.
   std::string copy_source_;
 
-  // If non-NULL, these are GUnixInputStream objects for the opened
+  // If non-null, these are GUnixInputStream objects for the opened
   // source/destination partitions.
   GInputStream* src_stream_;
   GOutputStream* dst_stream_;
diff --git a/filesystem_copier_action_unittest.cc b/filesystem_copier_action_unittest.cc
index 024b743..131feb8 100644
--- a/filesystem_copier_action_unittest.cc
+++ b/filesystem_copier_action_unittest.cc
@@ -132,8 +132,8 @@
   string a_loop_file;
   string b_loop_file;
 
-  if (!(utils::MakeTempFile("a_loop_file.XXXXXX", &a_loop_file, NULL) &&
-        utils::MakeTempFile("b_loop_file.XXXXXX", &b_loop_file, NULL))) {
+  if (!(utils::MakeTempFile("a_loop_file.XXXXXX", &a_loop_file, nullptr) &&
+        utils::MakeTempFile("b_loop_file.XXXXXX", &b_loop_file, nullptr))) {
     ADD_FAILURE();
     return false;
   }
@@ -406,9 +406,9 @@
 
 TEST_F(FilesystemCopierActionTest, RunAsRootDetermineFilesystemSizeTest) {
   string img;
-  EXPECT_TRUE(utils::MakeTempFile("img.XXXXXX", &img, NULL));
+  EXPECT_TRUE(utils::MakeTempFile("img.XXXXXX", &img, nullptr));
   ScopedPathUnlinker img_unlinker(img);
-  CreateExtImageAtPath(img, NULL);
+  CreateExtImageAtPath(img, nullptr);
   // Extend the "partition" holding the file system from 10MiB to 20MiB.
   EXPECT_EQ(0, System(base::StringPrintf(
       "dd if=/dev/zero of=%s seek=20971519 bs=1 count=1",
diff --git a/glib_utils.cc b/glib_utils.cc
index 523a16f..3371da4 100644
--- a/glib_utils.cc
+++ b/glib_utils.cc
@@ -20,7 +20,7 @@
                          (*error)->code,
                          (*error)->message ? (*error)->message : "(unknown)");
   g_error_free(*error);
-  *error = NULL;
+  *error = nullptr;
   return message;
 }
 
diff --git a/glib_utils.h b/glib_utils.h
index 9fea076..0c941ca 100644
--- a/glib_utils.h
+++ b/glib_utils.h
@@ -13,7 +13,7 @@
 namespace utils {
 
 // Returns the error message, if any, from a GError pointer. Frees the GError
-// object and resets error to NULL.
+// object and resets error to null.
 std::string GetAndFreeGError(GError** error);
 
 }  // namespace utils
diff --git a/hardware.cc b/hardware.cc
index a83d1b3..74de45a 100644
--- a/hardware.cc
+++ b/hardware.cc
@@ -169,7 +169,7 @@
 
   const char *rv = VbGetSystemPropertyString(key.c_str(), value_buffer,
                                              sizeof(value_buffer));
-  if (rv != NULL) {
+  if (rv != nullptr) {
     string return_value(value_buffer);
     base::TrimWhitespaceASCII(return_value, base::TRIM_ALL, &return_value);
     return return_value;
diff --git a/http_common.cc b/http_common.cc
index a3bd7f8..8cdc6eb 100644
--- a/http_common.cc
+++ b/http_common.cc
@@ -50,7 +50,7 @@
 }
 
 HttpResponseCode StringToHttpResponseCode(const char *s) {
-  return static_cast<HttpResponseCode>(strtoul(s, NULL, 10));
+  return static_cast<HttpResponseCode>(strtoul(s, nullptr, 10));
 }
 
 
@@ -68,7 +68,7 @@
     if ((is_found = (http_content_type_table[i].type == type)))
       break;
 
-  return (is_found ? http_content_type_table[i].str : NULL);
+  return (is_found ? http_content_type_table[i].str : nullptr);
 }
 
 }  // namespace chromeos_update_engine
diff --git a/http_fetcher.cc b/http_fetcher.cc
index 7fa2812..91aa177 100644
--- a/http_fetcher.cc
+++ b/http_fetcher.cc
@@ -41,7 +41,7 @@
         utils::GlibDestroyClosure);
     return true;
   }
-  CHECK_EQ(reinterpret_cast<Closure*>(NULL), callback_);
+  CHECK_EQ(static_cast<Closure*>(nullptr), callback_);
   callback_ = callback;
   return proxy_resolver_->GetProxiesForUrl(url,
                                            &HttpFetcher::StaticProxiesResolved,
@@ -52,9 +52,9 @@
   no_resolver_idle_id_ = 0;
   if (!proxies.empty())
     SetProxies(proxies);
-  CHECK_NE(reinterpret_cast<Closure*>(NULL), callback_);
+  CHECK_NE(static_cast<Closure*>(nullptr), callback_);
   Closure* callback = callback_;
-  callback_ = NULL;
+  callback_ = nullptr;
   // This may indirectly call back into ResolveProxiesForUrl():
   callback->Run();
   delete callback;
diff --git a/http_fetcher.h b/http_fetcher.h
index bab19d9..9c92abb 100644
--- a/http_fetcher.h
+++ b/http_fetcher.h
@@ -37,11 +37,11 @@
   HttpFetcher(ProxyResolver* proxy_resolver, SystemState* system_state)
       : post_data_set_(false),
         http_response_code_(0),
-        delegate_(NULL),
+        delegate_(nullptr),
         proxies_(1, kNoProxy),
         proxy_resolver_(proxy_resolver),
         no_resolver_idle_id_(0),
-        callback_(NULL),
+        callback_(nullptr),
         system_state_(system_state) {}
   virtual ~HttpFetcher();
 
@@ -137,7 +137,7 @@
   // set to the response code when the transfer is complete.
   int http_response_code_;
 
-  // The delegate; may be NULL.
+  // The delegate; may be null.
   HttpFetcherDelegate* delegate_;
 
   // Proxy servers
diff --git a/http_fetcher_unittest.cc b/http_fetcher_unittest.cc
index 3879bc4..ec074d7 100644
--- a/http_fetcher_unittest.cc
+++ b/http_fetcher_unittest.cc
@@ -95,11 +95,13 @@
     // Spawn the server process.
     gchar *argv[] = {
       const_cast<gchar*>("./test_http_server"),
-      NULL };
+      nullptr
+    };
     GError *err;
     gint server_stdout = -1;
-    if (!g_spawn_async_with_pipes(NULL, argv, NULL, G_SPAWN_DO_NOT_REAP_CHILD,
-                                  NULL, NULL, &pid_, NULL, &server_stdout, NULL,
+    if (!g_spawn_async_with_pipes(nullptr, argv, nullptr,
+                                  G_SPAWN_DO_NOT_REAP_CHILD, nullptr, nullptr,
+                                  &pid_, nullptr, &server_stdout, nullptr,
                                   &err)) {
       LOG(ERROR) << "failed to spawn http server process";
       return;
@@ -612,8 +614,8 @@
     GSource* timeout_source_;
     timeout_source_ = g_timeout_source_new(0);  // ms
     g_source_set_callback(timeout_source_, AbortingTimeoutCallback, &delegate,
-                          NULL);
-    g_source_attach(timeout_source_, NULL);
+                          nullptr);
+    g_source_attach(timeout_source_, nullptr);
     delegate.fetcher_->BeginTransfer(this->test_.BigUrl(server->GetPort()));
 
     g_main_loop_run(loop);
@@ -686,7 +688,7 @@
 class FailureHttpFetcherTestDelegate : public HttpFetcherDelegate {
  public:
   explicit FailureHttpFetcherTestDelegate(PythonHttpServer* server)
-      : loop_(NULL),
+      : loop_(nullptr),
         server_(server) {}
 
   virtual ~FailureHttpFetcherTestDelegate() {
@@ -703,7 +705,7 @@
       LOG(INFO) << "Stopping server in ReceivedBytes";
       delete server_;
       LOG(INFO) << "server stopped";
-      server_ = NULL;
+      server_ = nullptr;
     }
   }
   virtual void TransferComplete(HttpFetcher* fetcher, bool successful) {
@@ -727,7 +729,7 @@
     return;
   GMainLoop* loop = g_main_loop_new(g_main_context_default(), FALSE);
   {
-    FailureHttpFetcherTestDelegate delegate(NULL);
+    FailureHttpFetcherTestDelegate delegate(nullptr);
     delegate.loop_ = loop;
     scoped_ptr<HttpFetcher> fetcher(this->test_.NewSmallFetcher());
     fetcher->set_delegate(&delegate);
@@ -906,7 +908,7 @@
     if (expected_response_code_ != 0)
       EXPECT_EQ(expected_response_code_, fetcher->http_response_code());
     // Destroy the fetcher (because we're allowed to).
-    fetcher_.reset(NULL);
+    fetcher_.reset(nullptr);
     g_main_loop_quit(loop_);
   }
 
diff --git a/libcurl_http_fetcher.cc b/libcurl_http_fetcher.cc
index da643bf..64680c1 100644
--- a/libcurl_http_fetcher.cc
+++ b/libcurl_http_fetcher.cc
@@ -105,7 +105,8 @@
       const string content_type_attr =
         base::StringPrintf("Content-Type: %s",
                            GetHttpContentTypeString(post_content_type_));
-      curl_http_headers_ = curl_slist_append(NULL, content_type_attr.c_str());
+      curl_http_headers_ = curl_slist_append(nullptr,
+                                             content_type_attr.c_str());
       CHECK(curl_http_headers_);
       CHECK_EQ(
           curl_easy_setopt(curl_handle_, CURLOPT_HTTPHEADER,
@@ -476,8 +477,9 @@
   if (!timeout_source_) {
     LOG(INFO) << "Setting up timeout source: " << idle_seconds_ << " seconds.";
     timeout_source_ = g_timeout_source_new_seconds(idle_seconds_);
-    g_source_set_callback(timeout_source_, StaticTimeoutCallback, this, NULL);
-    g_source_attach(timeout_source_, NULL);
+    g_source_set_callback(timeout_source_, StaticTimeoutCallback, this,
+                          nullptr);
+    g_source_attach(timeout_source_, nullptr);
   }
 }
 
@@ -510,7 +512,7 @@
 void LibcurlHttpFetcher::CleanUp() {
   if (timeout_source_) {
     g_source_destroy(timeout_source_);
-    timeout_source_ = NULL;
+    timeout_source_ = nullptr;
   }
 
   for (size_t t = 0; t < arraysize(io_channels_); ++t) {
@@ -524,7 +526,7 @@
 
   if (curl_http_headers_) {
     curl_slist_free_all(curl_http_headers_);
-    curl_http_headers_ = NULL;
+    curl_http_headers_ = nullptr;
   }
   if (curl_handle_) {
     if (curl_multi_handle_) {
@@ -532,11 +534,11 @@
                CURLM_OK);
     }
     curl_easy_cleanup(curl_handle_);
-    curl_handle_ = NULL;
+    curl_handle_ = nullptr;
   }
   if (curl_multi_handle_) {
     CHECK_EQ(curl_multi_cleanup(curl_multi_handle_), CURLM_OK);
-    curl_multi_handle_ = NULL;
+    curl_multi_handle_ = nullptr;
   }
   transfer_in_progress_ = false;
 }
diff --git a/libcurl_http_fetcher.h b/libcurl_http_fetcher.h
index 495a2a9..c59ca05 100644
--- a/libcurl_http_fetcher.h
+++ b/libcurl_http_fetcher.h
@@ -30,10 +30,10 @@
   LibcurlHttpFetcher(ProxyResolver* proxy_resolver,
                      SystemState* system_state)
       : HttpFetcher(proxy_resolver, system_state),
-        curl_multi_handle_(NULL),
-        curl_handle_(NULL),
-        curl_http_headers_(NULL),
-        timeout_source_(NULL),
+        curl_multi_handle_(nullptr),
+        curl_handle_(nullptr),
+        curl_http_headers_(nullptr),
+        timeout_source_(nullptr),
         transfer_in_progress_(false),
         transfer_size_(0),
         bytes_downloaded_(0),
@@ -218,7 +218,7 @@
   typedef std::map<int, std::pair<GIOChannel*, guint>> IOChannels;
   IOChannels io_channels_[2];
 
-  // if non-NULL, a timer we're waiting on. glib main loop will call us back
+  // if non-null, a timer we're waiting on. glib main loop will call us back
   // when it fires.
   GSource* timeout_source_;
 
diff --git a/mock_http_fetcher.cc b/mock_http_fetcher.cc
index 9b3ae86..e178a50 100644
--- a/mock_http_fetcher.cc
+++ b/mock_http_fetcher.cc
@@ -31,7 +31,7 @@
 }
 
 // Returns false on one condition: If timeout_source_ was already set
-// and it needs to be deleted by the caller. If timeout_source_ is NULL
+// and it needs to be deleted by the caller. If timeout_source_ is null
 // when this function is called, this function will always return true.
 bool MockHttpFetcher::SendData(bool skip_delivery) {
   if (fail_transfer_) {
@@ -72,8 +72,8 @@
     timeout_source_ = g_timeout_source_new(10);
     CHECK(timeout_source_);
     g_source_set_callback(timeout_source_, StaticTimeoutCallback, this,
-                          NULL);
-    timout_tag_ = g_source_attach(timeout_source_, NULL);
+                          nullptr);
+    timout_tag_ = g_source_attach(timeout_source_, nullptr);
   }
   return true;
 }
@@ -82,7 +82,7 @@
   CHECK(!paused_);
   bool ret = SendData(false);
   if (false == ret) {
-    timeout_source_ = NULL;
+    timeout_source_ = nullptr;
   }
   return ret;
 }
@@ -96,7 +96,7 @@
   if (timeout_source_) {
     g_source_remove(timout_tag_);
     g_source_destroy(timeout_source_);
-    timeout_source_ = NULL;
+    timeout_source_ = nullptr;
   }
   delegate_->TransferTerminated(this);
 }
@@ -107,7 +107,7 @@
   if (timeout_source_) {
     g_source_remove(timout_tag_);
     g_source_destroy(timeout_source_);
-    timeout_source_ = NULL;
+    timeout_source_ = nullptr;
   }
 }
 
diff --git a/mock_http_fetcher.h b/mock_http_fetcher.h
index 748acf1..4bf1685 100644
--- a/mock_http_fetcher.h
+++ b/mock_http_fetcher.h
@@ -36,7 +36,7 @@
                   ProxyResolver* proxy_resolver)
       : HttpFetcher(proxy_resolver, &fake_system_state_),
         sent_size_(0),
-        timeout_source_(NULL),
+        timeout_source_(nullptr),
         timout_tag_(0),
         paused_(false),
         fail_transfer_(false),
@@ -120,7 +120,7 @@
   // time out for 0s just to make sure that run loop services other clients.
   GSource* timeout_source_;
 
-  // ID of the timeout source, valid only if timeout_source_ != NULL
+  // ID of the timeout source, valid only if timeout_source_ != null
   guint timout_tag_;
 
   // True iff the fetcher is paused.
diff --git a/omaha_hash_calculator.cc b/omaha_hash_calculator.cc
index 1b61a9d..af39611 100644
--- a/omaha_hash_calculator.cc
+++ b/omaha_hash_calculator.cc
@@ -46,7 +46,7 @@
   void FreeCurrentBio() {
     if (bio_) {
       BIO_free_all(bio_);
-      bio_ = NULL;
+      bio_ = nullptr;
     }
   }
 
@@ -114,13 +114,13 @@
     if (success)
       success = (BIO_flush(b64) == 1);
 
-    BUF_MEM *bptr = NULL;
+    BUF_MEM *bptr = nullptr;
     BIO_get_mem_ptr(b64, &bptr);
     out->assign(bptr->data, bptr->length - 1);
   }
   if (b64) {
     BIO_free_all(b64);
-    b64 = NULL;
+    b64 = nullptr;
   }
   return success;
 }
diff --git a/omaha_hash_calculator_unittest.cc b/omaha_hash_calculator_unittest.cc
index 93a7125..762a528 100644
--- a/omaha_hash_calculator_unittest.cc
+++ b/omaha_hash_calculator_unittest.cc
@@ -103,7 +103,7 @@
 TEST_F(OmahaHashCalculatorTest, UpdateFileSimpleTest) {
   string data_path;
   ASSERT_TRUE(
-      utils::MakeTempFile("data.XXXXXX", &data_path, NULL));
+      utils::MakeTempFile("data.XXXXXX", &data_path, nullptr));
   ScopedPathUnlinker data_path_unlinker(data_path);
   ASSERT_TRUE(utils::WriteFile(data_path.c_str(), "hi", 2));
 
@@ -128,7 +128,7 @@
 TEST_F(OmahaHashCalculatorTest, RawHashOfFileSimpleTest) {
   string data_path;
   ASSERT_TRUE(
-      utils::MakeTempFile("data.XXXXXX", &data_path, NULL));
+      utils::MakeTempFile("data.XXXXXX", &data_path, nullptr));
   ScopedPathUnlinker data_path_unlinker(data_path);
   ASSERT_TRUE(utils::WriteFile(data_path.c_str(), "hi", 2));
 
diff --git a/omaha_request_action.cc b/omaha_request_action.cc
index 1bd5041..ede4e64 100644
--- a/omaha_request_action.cc
+++ b/omaha_request_action.cc
@@ -101,7 +101,7 @@
                   int ping_roll_call_days,
                   PrefsInterface* prefs) {
   string app_body;
-  if (event == NULL) {
+  if (event == nullptr) {
     app_body = GetPingXml(ping_active_days, ping_roll_call_days);
     if (!ping_only) {
       // not passing update_disabled to Omaha because we want to
@@ -428,7 +428,7 @@
 // static
 int OmahaRequestAction::GetInstallDate(SystemState* system_state) {
   PrefsInterface* prefs = system_state->prefs();
-  if (prefs == NULL)
+  if (prefs == nullptr)
     return -1;
 
   // If we have the value stored on disk, just return it.
@@ -935,7 +935,7 @@
   int64_t manifest_metadata_size = 0;
   int64_t next_data_offset = 0;
   int64_t next_data_length = 0;
-  if (system_state_ != NULL &&
+  if (system_state_ &&
       system_state_->prefs()->GetInt64(kPrefsManifestMetadataSize,
                                        &manifest_metadata_size) &&
       manifest_metadata_size != -1 &&
@@ -948,7 +948,7 @@
   }
 
   string file_id = utils::CalculateP2PFileId(response.hash, response.size);
-  if (system_state_->p2p_manager() != NULL) {
+  if (system_state_->p2p_manager()) {
     LOG(INFO) << "Checking if payload is available via p2p, file_id="
               << file_id << " minimum_size=" << minimum_size;
     system_state_->p2p_manager()->LookupUrlForFile(
@@ -1190,7 +1190,7 @@
 // static
 bool OmahaRequestAction::HasInstallDate(SystemState *system_state) {
   PrefsInterface* prefs = system_state->prefs();
-  if (prefs == NULL)
+  if (prefs == nullptr)
     return false;
 
   return prefs->Exists(kPrefsInstallDateDays);
@@ -1204,7 +1204,7 @@
   TEST_AND_RETURN_FALSE(install_date_days >= 0);
 
   PrefsInterface* prefs = system_state->prefs();
-  if (prefs == NULL)
+  if (prefs == nullptr)
     return false;
 
   if (!prefs->SetInt64(kPrefsInstallDateDays, install_date_days))
diff --git a/omaha_request_action.h b/omaha_request_action.h
index 0dc3d9f..a4d9fdf 100644
--- a/omaha_request_action.h
+++ b/omaha_request_action.h
@@ -112,14 +112,14 @@
   //
   // Takes ownership of the passed in HttpFetcher. Useful for testing.
   //
-  // Takes ownership of the passed in OmahaEvent. If |event| is NULL,
+  // Takes ownership of the passed in OmahaEvent. If |event| is null,
   // this is an UpdateCheck request, otherwise it's an Event request.
   // Event requests always succeed.
   //
   // A good calling pattern is:
   // OmahaRequestAction(..., new OmahaEvent(...), new WhateverHttpFetcher);
   // or
-  // OmahaRequestAction(..., NULL, new WhateverHttpFetcher);
+  // OmahaRequestAction(..., nullptr, new WhateverHttpFetcher);
   OmahaRequestAction(SystemState* system_state,
                      OmahaEvent* event,
                      HttpFetcher* http_fetcher,
@@ -143,7 +143,7 @@
 
   virtual void TransferComplete(HttpFetcher *fetcher, bool successful);
   // Returns true if this is an Event request, false if it's an UpdateCheck.
-  bool IsEvent() const { return event_.get() != NULL; }
+  bool IsEvent() const { return event_.get() != nullptr; }
 
  private:
   FRIEND_TEST(OmahaRequestActionTest, GetInstallDate);
@@ -264,7 +264,7 @@
   // Contains state that is relevant in the processing of the Omaha request.
   OmahaRequestParams* params_;
 
-  // Pointer to the OmahaEvent info. This is an UpdateCheck request if NULL.
+  // Pointer to the OmahaEvent info. This is an UpdateCheck request if null.
   scoped_ptr<OmahaEvent> event_;
 
   // pointer to the HttpFetcher that does the http work
diff --git a/omaha_request_action_unittest.cc b/omaha_request_action_unittest.cc
index 6d960e2..572721d 100644
--- a/omaha_request_action_unittest.cc
+++ b/omaha_request_action_unittest.cc
@@ -159,7 +159,7 @@
 class OmahaRequestActionTestProcessorDelegate : public ActionProcessorDelegate {
  public:
   OmahaRequestActionTestProcessorDelegate()
-      : loop_(NULL),
+      : loop_(nullptr),
         expected_code_(ErrorCode::kSuccess) {}
   virtual ~OmahaRequestActionTestProcessorDelegate() {
   }
@@ -224,11 +224,11 @@
 };
 
 // Returns true iff an output response was obtained from the
-// OmahaRequestAction. |prefs| may be NULL, in which case a local PrefsMock is
-// used. |payload_state| may be NULL, in which case a local mock is used.
-// |p2p_manager| may be NULL, in which case a local mock is used.
-// |connection_manager| may be NULL, in which case a local mock is used.
-// out_response may be NULL. If |fail_http_response_code| is non-negative,
+// OmahaRequestAction. |prefs| may be null, in which case a local PrefsMock
+// is used. |payload_state| may be null, in which case a local mock is used.
+// |p2p_manager| may be null, in which case a local mock is used.
+// |connection_manager| may be null, in which case a local mock is used.
+// out_response may be null. If |fail_http_response_code| is non-negative,
 // the transfer will fail with that code. |ping_only| is passed through to the
 // OmahaRequestAction constructor. out_post_data may be null; if non-null, the
 // post-data received by the mock HttpFetcher is returned.
@@ -255,7 +255,7 @@
   GMainLoop* loop = g_main_loop_new(g_main_context_default(), FALSE);
   MockHttpFetcher* fetcher = new MockHttpFetcher(http_response.data(),
                                                  http_response.size(),
-                                                 NULL);
+                                                 nullptr);
   if (fail_http_response_code >= 0) {
     fetcher->FailTransfer(fail_http_response_code);
   }
@@ -270,7 +270,7 @@
     fake_system_state.set_connection_manager(connection_manager);
   fake_system_state.set_request_params(params);
   OmahaRequestAction action(&fake_system_state,
-                            NULL,
+                            nullptr,
                             fetcher,
                             ping_only);
   OmahaRequestActionTestProcessorDelegate delegate;
@@ -323,7 +323,7 @@
   GMainLoop* loop = g_main_loop_new(g_main_context_default(), FALSE);
   MockHttpFetcher* fetcher = new MockHttpFetcher(http_response.data(),
                                                  http_response.size(),
-                                                 NULL);
+                                                 nullptr);
   FakeSystemState fake_system_state;
   fake_system_state.set_request_params(&params);
   OmahaRequestAction action(&fake_system_state, event, fetcher, false);
@@ -343,10 +343,10 @@
 TEST(OmahaRequestActionTest, RejectEntities) {
   OmahaResponse response;
   ASSERT_FALSE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetNoUpdateResponseWithEntity(OmahaRequestParams::kAppId),
                       -1,
@@ -356,17 +356,17 @@
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
 TEST(OmahaRequestActionTest, NoUpdateTest) {
   OmahaResponse response;
   ASSERT_TRUE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetNoUpdateResponse(OmahaRequestParams::kAppId),
                       -1,
@@ -376,17 +376,17 @@
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
 TEST(OmahaRequestActionTest, ValidUpdateTest) {
   OmahaResponse response;
   ASSERT_TRUE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetUpdateResponse(OmahaRequestParams::kAppId,
                                         "1.2.3.4",  // version
@@ -405,7 +405,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_TRUE(response.update_exists);
   EXPECT_TRUE(response.update_exists);
   EXPECT_EQ("1.2.3.4", response.version);
@@ -422,10 +422,10 @@
   OmahaRequestParams params = kDefaultTestParams;
   params.set_update_disabled(true);
   ASSERT_FALSE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse(OmahaRequestParams::kAppId,
                                         "1.2.3.4",  // version
@@ -444,7 +444,7 @@
                       metrics::CheckReaction::kIgnored,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
@@ -452,7 +452,7 @@
   OmahaResponse response;
   // Set up a connection manager that doesn't allow a valid update over
   // the current ethernet connection.
-  MockConnectionManager mock_cm(NULL);
+  MockConnectionManager mock_cm(nullptr);
   EXPECT_CALL(mock_cm, GetConnectionProperties(_, _, _))
     .WillRepeatedly(DoAll(SetArgumentPointee<1>(kNetEthernet),
                           SetArgumentPointee<2>(NetworkTethering::kUnknown),
@@ -463,9 +463,9 @@
     .WillRepeatedly(Return(shill::kTypeEthernet));
 
   ASSERT_FALSE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
                       &mock_cm,  // connection_manager
                       &kDefaultTestParams,
                       GetUpdateResponse(OmahaRequestParams::kAppId,
@@ -485,7 +485,7 @@
                       metrics::CheckReaction::kIgnored,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
@@ -498,10 +498,10 @@
     .WillRepeatedly(Return(rollback_version));
 
   ASSERT_FALSE(
-      TestUpdateCheck(NULL,  // prefs
+      TestUpdateCheck(nullptr,  // prefs
                       &mock_payload_state,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetUpdateResponse(OmahaRequestParams::kAppId,
                                         rollback_version,  // version
@@ -520,7 +520,7 @@
                       metrics::CheckReaction::kIgnored,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
@@ -529,10 +529,10 @@
   OmahaRequestParams params = kDefaultTestParams;
   params.set_update_disabled(true);
   ASSERT_TRUE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetNoUpdateResponse(OmahaRequestParams::kAppId),
                       -1,
@@ -542,7 +542,7 @@
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
@@ -564,9 +564,9 @@
 
   ASSERT_FALSE(
       TestUpdateCheck(&prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -589,16 +589,16 @@
                       metrics::CheckReaction::kDeferring,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 
   // Verify if we are interactive check we don't defer.
   params.set_interactive(true);
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -621,7 +621,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_TRUE(response.update_exists);
 }
 
@@ -646,9 +646,9 @@
 
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -671,7 +671,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_TRUE(response.update_exists);
 }
 
@@ -696,9 +696,9 @@
 
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -721,7 +721,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_TRUE(response.update_exists);
 }
 
@@ -747,9 +747,9 @@
 
   ASSERT_TRUE(TestUpdateCheck(
                       &prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -772,7 +772,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
 
   int64_t count;
   ASSERT_TRUE(prefs.GetInt64(kPrefsUpdateCheckCount, &count));
@@ -801,9 +801,9 @@
 
   ASSERT_FALSE(TestUpdateCheck(
                       &prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,    // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -826,7 +826,7 @@
                       metrics::CheckReaction::kDeferring,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
 
   int64_t count;
   ASSERT_TRUE(prefs.GetInt64(kPrefsUpdateCheckCount, &count));
@@ -837,9 +837,9 @@
   params.set_interactive(true);
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -862,7 +862,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_TRUE(response.update_exists);
 }
 
@@ -889,9 +889,9 @@
 
   ASSERT_FALSE(TestUpdateCheck(
                       &prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -914,7 +914,7 @@
                       metrics::CheckReaction::kDeferring,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
 
   int64_t count;
   ASSERT_TRUE(prefs.GetInt64(kPrefsUpdateCheckCount, &count));
@@ -927,9 +927,9 @@
   params.set_interactive(true);
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -952,7 +952,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_TRUE(response.update_exists);
 }
 
@@ -964,10 +964,10 @@
   FakeSystemState fake_system_state;
   OmahaRequestParams params = kDefaultTestParams;
   fake_system_state.set_request_params(&params);
-  OmahaRequestAction action(&fake_system_state, NULL,
+  OmahaRequestAction action(&fake_system_state, nullptr,
                             new MockHttpFetcher(http_response.data(),
                                                 http_response.size(),
-                                                NULL),
+                                                nullptr),
                             false);
   OmahaRequestActionTestProcessorDelegate delegate;
   delegate.loop_ = loop;
@@ -984,10 +984,10 @@
 TEST(OmahaRequestActionTest, InvalidXmlTest) {
   OmahaResponse response;
   ASSERT_FALSE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       "invalid xml>",
                       -1,
@@ -997,17 +997,17 @@
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
 TEST(OmahaRequestActionTest, EmptyResponseTest) {
   OmahaResponse response;
   ASSERT_FALSE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       "",
                       -1,
@@ -1017,17 +1017,17 @@
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
 TEST(OmahaRequestActionTest, MissingStatusTest) {
   OmahaResponse response;
   ASSERT_FALSE(TestUpdateCheck(
-      NULL,  // prefs
-      NULL,  // payload_state
-      NULL,  // p2p_manager
-      NULL,  // connection_manager
+      nullptr,  // prefs
+      nullptr,  // payload_state
+      nullptr,  // p2p_manager
+      nullptr,  // connection_manager
       &kDefaultTestParams,
       "<?xml version=\"1.0\" encoding=\"UTF-8\"?><response protocol=\"3.0\">"
       "<daystart elapsed_seconds=\"100\"/>"
@@ -1041,17 +1041,17 @@
       metrics::CheckReaction::kUnset,
       metrics::DownloadErrorCode::kUnset,
       &response,
-      NULL));
+      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
 TEST(OmahaRequestActionTest, InvalidStatusTest) {
   OmahaResponse response;
   ASSERT_FALSE(TestUpdateCheck(
-      NULL,  // prefs
-      NULL,  // payload_state
-      NULL,  // p2p_manager
-      NULL,  // connection_manager
+      nullptr,  // prefs
+      nullptr,  // payload_state
+      nullptr,  // p2p_manager
+      nullptr,  // connection_manager
       &kDefaultTestParams,
       "<?xml version=\"1.0\" encoding=\"UTF-8\"?><response protocol=\"3.0\">"
       "<daystart elapsed_seconds=\"100\"/>"
@@ -1065,17 +1065,17 @@
       metrics::CheckReaction::kUnset,
       metrics::DownloadErrorCode::kUnset,
       &response,
-      NULL));
+      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
 TEST(OmahaRequestActionTest, MissingNodesetTest) {
   OmahaResponse response;
   ASSERT_FALSE(TestUpdateCheck(
-      NULL,  // prefs
-      NULL,  // payload_state
-      NULL,  // p2p_manager
-      NULL,  // connection_manager
+      nullptr,  // prefs
+      nullptr,  // payload_state
+      nullptr,  // p2p_manager
+      nullptr,  // connection_manager
       &kDefaultTestParams,
       "<?xml version=\"1.0\" encoding=\"UTF-8\"?><response protocol=\"3.0\">"
       "<daystart elapsed_seconds=\"100\"/>"
@@ -1089,7 +1089,7 @@
       metrics::CheckReaction::kUnset,
       metrics::DownloadErrorCode::kUnset,
       &response,
-      NULL));
+      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
@@ -1114,10 +1114,10 @@
   LOG(INFO) << "Input Response = " << input_response;
 
   OmahaResponse response;
-  ASSERT_TRUE(TestUpdateCheck(NULL,  // prefs
-                              NULL,  // payload_state
-                              NULL,  // p2p_manager
-                              NULL,  // connection_manager
+  ASSERT_TRUE(TestUpdateCheck(nullptr,  // prefs
+                              nullptr,  // payload_state
+                              nullptr,  // p2p_manager
+                              nullptr,  // connection_manager
                               &kDefaultTestParams,
                               input_response,
                               -1,
@@ -1127,7 +1127,7 @@
                               metrics::CheckReaction::kUpdating,
                               metrics::DownloadErrorCode::kUnset,
                               &response,
-                              NULL));
+                              nullptr));
   EXPECT_TRUE(response.update_exists);
   EXPECT_EQ("10.2.3.4", response.version);
   EXPECT_EQ("http://missing/field/test/f", response.payload_urls[0]);
@@ -1164,10 +1164,10 @@
   FakeSystemState fake_system_state;
   OmahaRequestParams params = kDefaultTestParams;
   fake_system_state.set_request_params(&params);
-  OmahaRequestAction action(&fake_system_state, NULL,
+  OmahaRequestAction action(&fake_system_state, nullptr,
                             new MockHttpFetcher(http_response.data(),
                                                 http_response.size(),
-                                                NULL),
+                                                nullptr),
                             false);
   TerminateEarlyTestProcessorDelegate delegate;
   delegate.loop_ = loop;
@@ -1211,10 +1211,10 @@
                             false);  // use_p2p_for_sharing
   OmahaResponse response;
   ASSERT_FALSE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       "invalid xml>",
                       -1,
@@ -1240,10 +1240,10 @@
 TEST(OmahaRequestActionTest, XmlDecodeTest) {
   OmahaResponse response;
   ASSERT_TRUE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetUpdateResponse(OmahaRequestParams::kAppId,
                                         "1.2.3.4",  // version
@@ -1262,7 +1262,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
 
   EXPECT_EQ(response.more_info_url, "testthe<url");
   EXPECT_EQ(response.payload_urls[0], "testthe&codebase/file.signed");
@@ -1272,10 +1272,10 @@
 TEST(OmahaRequestActionTest, ParseIntTest) {
   OmahaResponse response;
   ASSERT_TRUE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetUpdateResponse(OmahaRequestParams::kAppId,
                                         "1.2.3.4",  // version
@@ -1295,7 +1295,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
 
   EXPECT_EQ(response.size, 123123123123123ll);
 }
@@ -1307,9 +1307,9 @@
       .WillOnce(DoAll(SetArgumentPointee<1>(string("")), Return(true)));
   EXPECT_CALL(prefs, SetString(kPrefsPreviousVersion, _)).Times(1);
   ASSERT_FALSE(TestUpdateCheck(&prefs,
-                               NULL,  // payload_state
-                               NULL,  // p2p_manager
-                               NULL,  // connection_manager
+                               nullptr,  // payload_state
+                               nullptr,  // p2p_manager
+                               nullptr,  // connection_manager
                                &kDefaultTestParams,
                                "invalid xml>",
                                -1,
@@ -1318,7 +1318,7 @@
                                metrics::CheckResult::kParsingError,
                                metrics::CheckReaction::kUnset,
                                metrics::DownloadErrorCode::kUnset,
-                               NULL,  // response
+                               nullptr,  // response
                                &post_data));
   // convert post_data to string
   string post_str(&post_data[0], post_data.size());
@@ -1344,9 +1344,9 @@
   OmahaRequestParams params = kDefaultTestParams;
   params.set_update_disabled(true);
   ASSERT_FALSE(TestUpdateCheck(&prefs,
-                               NULL,  // payload_state
-                               NULL,  // p2p_manager
-                               NULL,  // connection_manager
+                               nullptr,  // payload_state
+                               nullptr,  // p2p_manager
+                               nullptr,  // connection_manager
                                &params,
                                "invalid xml>",
                                -1,
@@ -1355,7 +1355,7 @@
                                metrics::CheckResult::kParsingError,
                                metrics::CheckReaction::kUnset,
                                metrics::DownloadErrorCode::kUnset,
-                               NULL,  // response
+                               nullptr,  // response
                                &post_data));
   // convert post_data to string
   string post_str(&post_data[0], post_data.size());
@@ -1415,10 +1415,10 @@
   fake_system_state.set_request_params(&params);
   OmahaRequestAction update_check_action(
       &fake_system_state,
-      NULL,
+      nullptr,
       new MockHttpFetcher(http_response.data(),
                           http_response.size(),
-                          NULL),
+                          nullptr),
       false);
   EXPECT_FALSE(update_check_action.IsEvent());
 
@@ -1429,7 +1429,7 @@
       new OmahaEvent(OmahaEvent::kTypeUpdateComplete),
       new MockHttpFetcher(http_response.data(),
                           http_response.size(),
-                          NULL),
+                          nullptr),
       false);
   EXPECT_TRUE(event_action.IsEvent());
 }
@@ -1459,10 +1459,10 @@
                               "",     // target_version_prefix
                               false,  // use_p2p_for_downloading
                               false);  // use_p2p_for_sharing
-    ASSERT_FALSE(TestUpdateCheck(NULL,  // prefs
-                                 NULL,  // payload_state
-                                 NULL,  // p2p_manager
-                                 NULL,  // connection_manager
+    ASSERT_FALSE(TestUpdateCheck(nullptr,  // prefs
+                                 nullptr,  // payload_state
+                                 nullptr,  // p2p_manager
+                                 nullptr,  // connection_manager
                                  &params,
                                  "invalid xml>",
                                  -1,
@@ -1471,7 +1471,7 @@
                                  metrics::CheckResult::kParsingError,
                                  metrics::CheckReaction::kUnset,
                                  metrics::DownloadErrorCode::kUnset,
-                                 NULL,
+                                 nullptr,
                                  &post_data));
     // convert post_data to string
     string post_str(post_data.data(), post_data.size());
@@ -1507,10 +1507,10 @@
                               "",     // target_version_prefix
                               false,  // use_p2p_for_downloading
                               false);  // use_p2p_for_sharing
-    ASSERT_FALSE(TestUpdateCheck(NULL,  // prefs
-                                 NULL,  // payload_state
-                                 NULL,  // p2p_manager
-                                 NULL,  // connection_manager
+    ASSERT_FALSE(TestUpdateCheck(nullptr,  // prefs
+                                 nullptr,  // payload_state
+                                 nullptr,  // p2p_manager
+                                 nullptr,  // connection_manager
                                  &params,
                                  "invalid xml>",
                                  -1,
@@ -1519,7 +1519,7 @@
                                  metrics::CheckResult::kParsingError,
                                  metrics::CheckReaction::kUnset,
                                  metrics::DownloadErrorCode::kUnset,
-                                 NULL,
+                                 nullptr,
                                  &post_data));
     // convert post_data to string
     string post_str(&post_data[0], post_data.size());
@@ -1569,9 +1569,9 @@
     vector<char> post_data;
     ASSERT_TRUE(
         TestUpdateCheck(&prefs,
-                        NULL,  // payload_state
-                        NULL,  // p2p_manager
-                        NULL,  // connection_manager
+                        nullptr,  // payload_state
+                        nullptr,  // p2p_manager
+                        nullptr,  // connection_manager
                         &kDefaultTestParams,
                         GetNoUpdateResponse(OmahaRequestParams::kAppId),
                         -1,
@@ -1580,7 +1580,7 @@
                         metrics::CheckResult::kUnset,
                         metrics::CheckReaction::kUnset,
                         metrics::DownloadErrorCode::kUnset,
-                        NULL,
+                        nullptr,
                         &post_data));
     string post_str(&post_data[0], post_data.size());
     EXPECT_NE(post_str.find("<ping active=\"1\" a=\"6\" r=\"5\"></ping>"),
@@ -1612,9 +1612,9 @@
   vector<char> post_data;
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetNoUpdateResponse(OmahaRequestParams::kAppId),
                       -1,
@@ -1623,7 +1623,7 @@
                       metrics::CheckResult::kNoUpdateAvailable,
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
-                      NULL,
+                      nullptr,
                       &post_data));
   string post_str(&post_data[0], post_data.size());
   EXPECT_NE(post_str.find("<ping active=\"1\" a=\"3\"></ping>"),
@@ -1647,9 +1647,9 @@
   vector<char> post_data;
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetNoUpdateResponse(OmahaRequestParams::kAppId),
                       -1,
@@ -1658,7 +1658,7 @@
                       metrics::CheckResult::kNoUpdateAvailable,
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
-                      NULL,
+                      nullptr,
                       &post_data));
   string post_str(&post_data[0], post_data.size());
   EXPECT_NE(post_str.find("<ping active=\"1\" r=\"4\"></ping>\n"),
@@ -1683,9 +1683,9 @@
   vector<char> post_data;
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetNoUpdateResponse(OmahaRequestParams::kAppId),
                       -1,
@@ -1694,7 +1694,7 @@
                       metrics::CheckResult::kNoUpdateAvailable,
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
-                      NULL,
+                      nullptr,
                       &post_data));
   string post_str(&post_data[0], post_data.size());
   EXPECT_EQ(post_str.find("ping"), string::npos);
@@ -1713,9 +1713,9 @@
   vector<char> post_data;
   EXPECT_TRUE(
       TestUpdateCheck(&prefs,
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetNoUpdateResponse(OmahaRequestParams::kAppId),
                       -1,
@@ -1724,7 +1724,7 @@
                       metrics::CheckResult::kUnset,
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
-                      NULL,
+                      nullptr,
                       &post_data));
   EXPECT_EQ(post_data.size(), 0);
 }
@@ -1749,9 +1749,9 @@
   vector<char> post_data;
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       "<?xml version=\"1.0\" encoding=\"UTF-8\"?><response "
                       "protocol=\"3.0\"><daystart elapsed_seconds=\"100\"/>"
@@ -1763,7 +1763,7 @@
                       metrics::CheckResult::kNoUpdateAvailable,
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
-                      NULL,
+                      nullptr,
                       &post_data));
   string post_str(&post_data[0], post_data.size());
   EXPECT_EQ(post_str.find("ping"), string::npos);
@@ -1789,9 +1789,9 @@
       .WillOnce(Return(true));
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       "<?xml version=\"1.0\" encoding=\"UTF-8\"?><response "
                       "protocol=\"3.0\"><daystart elapsed_seconds=\"200\"/>"
@@ -1803,8 +1803,8 @@
                       metrics::CheckResult::kNoUpdateAvailable,
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
-                      NULL,
-                      NULL));
+                      nullptr,
+                      nullptr));
 }
 
 TEST(OmahaRequestActionTest, NoElapsedSecondsTest) {
@@ -1815,9 +1815,9 @@
   EXPECT_CALL(prefs, SetInt64(kPrefsLastRollCallPingDay, _)).Times(0);
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       "<?xml version=\"1.0\" encoding=\"UTF-8\"?><response "
                       "protocol=\"3.0\"><daystart blah=\"200\"/>"
@@ -1829,8 +1829,8 @@
                       metrics::CheckResult::kNoUpdateAvailable,
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
-                      NULL,
-                      NULL));
+                      nullptr,
+                      nullptr));
 }
 
 TEST(OmahaRequestActionTest, BadElapsedSecondsTest) {
@@ -1841,9 +1841,9 @@
   EXPECT_CALL(prefs, SetInt64(kPrefsLastRollCallPingDay, _)).Times(0);
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       "<?xml version=\"1.0\" encoding=\"UTF-8\"?><response "
                       "protocol=\"3.0\"><daystart elapsed_seconds=\"x\"/>"
@@ -1855,16 +1855,16 @@
                       metrics::CheckResult::kNoUpdateAvailable,
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kUnset,
-                      NULL,
-                      NULL));
+                      nullptr,
+                      nullptr));
 }
 
 TEST(OmahaRequestActionTest, NoUniqueIDTest) {
   vector<char> post_data;
-  ASSERT_FALSE(TestUpdateCheck(NULL,  // prefs
-                               NULL,  // payload_state
-                               NULL,  // p2p_manager
-                               NULL,  // connection_manager
+  ASSERT_FALSE(TestUpdateCheck(nullptr,  // prefs
+                               nullptr,  // payload_state
+                               nullptr,  // p2p_manager
+                               nullptr,  // connection_manager
                                &kDefaultTestParams,
                                "invalid xml>",
                                -1,
@@ -1873,7 +1873,7 @@
                                metrics::CheckResult::kParsingError,
                                metrics::CheckReaction::kUnset,
                                metrics::DownloadErrorCode::kUnset,
-                               NULL,  // response
+                               nullptr,  // response
                                &post_data));
   // convert post_data to string
   string post_str(&post_data[0], post_data.size());
@@ -1886,10 +1886,10 @@
   const int http_error_code =
       static_cast<int>(ErrorCode::kOmahaRequestHTTPResponseBase) + 501;
   ASSERT_FALSE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       "",
                       501,
@@ -1899,7 +1899,7 @@
                       metrics::CheckReaction::kUnset,
                       static_cast<metrics::DownloadErrorCode>(501),
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
@@ -1908,10 +1908,10 @@
   const int http_error_code =
       static_cast<int>(ErrorCode::kOmahaRequestHTTPResponseBase) + 999;
   ASSERT_FALSE(
-      TestUpdateCheck(NULL,  // prefs
-                      NULL,  // payload_state
-                      NULL,  // p2p_manager
-                      NULL,  // connection_manager
+      TestUpdateCheck(nullptr,  // prefs
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       "",
                       1500,
@@ -1921,7 +1921,7 @@
                       metrics::CheckReaction::kUnset,
                       metrics::DownloadErrorCode::kHttpStatusOther,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_FALSE(response.update_exists);
 }
 
@@ -1943,9 +1943,9 @@
 
   ASSERT_FALSE(TestUpdateCheck(
                       &prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -1968,7 +1968,7 @@
                       metrics::CheckReaction::kDeferring,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
 
   int64_t timestamp = 0;
   ASSERT_TRUE(prefs.GetInt64(kPrefsUpdateFirstSeenAt, &timestamp));
@@ -1979,9 +1979,9 @@
   params.set_interactive(true);
   ASSERT_TRUE(
       TestUpdateCheck(&prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -2004,7 +2004,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_TRUE(response.update_exists);
 }
 
@@ -2031,9 +2031,9 @@
   ASSERT_TRUE(prefs.SetInt64(kPrefsUpdateFirstSeenAt, t1.ToInternalValue()));
   ASSERT_TRUE(TestUpdateCheck(
                       &prefs,  // prefs
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -2056,7 +2056,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
 
   EXPECT_TRUE(response.update_exists);
 
@@ -2095,9 +2095,9 @@
   EXPECT_TRUE(params.to_more_stable_channel());
   EXPECT_TRUE(params.is_powerwash_allowed());
   ASSERT_FALSE(TestUpdateCheck(&prefs,
-                               NULL,    // payload_state
-                               NULL,    // p2p_manager
-                               NULL,  // connection_manager
+                               nullptr,  // payload_state
+                               nullptr,  // p2p_manager
+                               nullptr,  // connection_manager
                                &params,
                                "invalid xml>",
                                -1,
@@ -2106,7 +2106,7 @@
                                metrics::CheckResult::kParsingError,
                                metrics::CheckReaction::kUnset,
                                metrics::DownloadErrorCode::kUnset,
-                               NULL,  // response
+                               nullptr,  // response
                                &post_data));
   // convert post_data to string
   string post_str(&post_data[0], post_data.size());
@@ -2146,9 +2146,9 @@
   EXPECT_FALSE(params.to_more_stable_channel());
   EXPECT_FALSE(params.is_powerwash_allowed());
   ASSERT_FALSE(TestUpdateCheck(&prefs,
-                               NULL,    // payload_state
-                               NULL,    // p2p_manager
-                               NULL,  // connection_manager
+                               nullptr,  // payload_state
+                               nullptr,  // p2p_manager
+                               nullptr,  // connection_manager
                                &params,
                                "invalid xml>",
                                -1,
@@ -2157,7 +2157,7 @@
                                metrics::CheckResult::kParsingError,
                                metrics::CheckReaction::kUnset,
                                metrics::DownloadErrorCode::kUnset,
-                               NULL,  // response
+                               nullptr,  // response
                                &post_data));
   // convert post_data to string
   string post_str(&post_data[0], post_data.size());
@@ -2196,10 +2196,10 @@
       .Times(expect_p2p_client_lookup ? 1 : 0);
 
   ASSERT_TRUE(
-      TestUpdateCheck(NULL,  // prefs
+      TestUpdateCheck(nullptr,  // prefs
                       &mock_payload_state,
                       &mock_p2p_manager,
-                      NULL,  // connection_manager
+                      nullptr,  // connection_manager
                       &request_params,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -2222,7 +2222,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       &response,
-                      NULL));
+                      nullptr));
   EXPECT_TRUE(response.update_exists);
 
   EXPECT_EQ(response.disable_p2p_for_downloading,
@@ -2322,9 +2322,9 @@
                             OmahaResponse *response) {
   return
       TestUpdateCheck(prefs,
-                      NULL,    // payload_state
-                      NULL,    // p2p_manager
-                      NULL,  // connection_manager
+                      nullptr,  // payload_state
+                      nullptr,  // p2p_manager
+                      nullptr,  // connection_manager
                       &kDefaultTestParams,
                       GetUpdateResponse2(OmahaRequestParams::kAppId,
                                          "1.2.3.4",  // version
@@ -2347,7 +2347,7 @@
                       metrics::CheckReaction::kUpdating,
                       metrics::DownloadErrorCode::kUnset,
                       response,
-                      NULL);
+                      nullptr);
 }
 
 TEST(OmahaRequestActionTest, ParseInstallDateFromResponse) {
diff --git a/omaha_request_params.cc b/omaha_request_params.cc
index 73117a4..71185f6 100644
--- a/omaha_request_params.cc
+++ b/omaha_request_params.cc
@@ -59,24 +59,24 @@
   os_platform_ = OmahaRequestParams::kOsPlatform;
   os_version_ = OmahaRequestParams::kOsVersion;
   app_version_ = in_app_version.empty() ?
-      GetLsbValue("CHROMEOS_RELEASE_VERSION", "", NULL, stateful_override) :
+      GetLsbValue("CHROMEOS_RELEASE_VERSION", "", nullptr, stateful_override) :
       in_app_version;
   os_sp_ = app_version_ + "_" + GetMachineType();
   os_board_ = GetLsbValue("CHROMEOS_RELEASE_BOARD",
                           "",
-                          NULL,
+                          nullptr,
                           stateful_override);
   string release_app_id = GetLsbValue("CHROMEOS_RELEASE_APPID",
                                       OmahaRequestParams::kAppId,
-                                      NULL,
+                                      nullptr,
                                       stateful_override);
   board_app_id_ = GetLsbValue("CHROMEOS_BOARD_APPID",
                               release_app_id,
-                              NULL,
+                              nullptr,
                               stateful_override);
   canary_app_id_ = GetLsbValue("CHROMEOS_CANARY_APPID",
                                release_app_id,
-                               NULL,
+                               nullptr,
                                stateful_override);
   app_lang_ = "en-US";
   hwid_ = system_state_->hardware()->GetHardwareClass();
@@ -103,7 +103,7 @@
   }
 
   if (in_update_url.empty())
-    update_url_ = GetLsbValue("CHROMEOS_AUSERVER", kProductionOmahaUrl, NULL,
+    update_url_ = GetLsbValue("CHROMEOS_AUSERVER", kProductionOmahaUrl, nullptr,
                               stateful_override);
   else
     update_url_ = in_update_url;
@@ -165,7 +165,7 @@
   string current_channel_new_value = GetLsbValue(
       kUpdateChannelKey,
       current_channel_,
-      NULL,  // No need to validate the read-only rootfs channel.
+      nullptr,  // No need to validate the read-only rootfs channel.
       false);  // stateful_override is false so we get the current channel.
 
   if (current_channel_ != current_channel_new_value) {
@@ -179,7 +179,7 @@
   string is_powerwash_allowed_str = GetLsbValue(
       kIsPowerwashAllowedKey,
       "false",
-      NULL,   // no need to validate
+      nullptr,  // no need to validate
       true);  // always get it from stateful, as that's the only place it'll be
   bool is_powerwash_allowed_new_value = (is_powerwash_allowed_str == "true");
   if (is_powerwash_allowed_ != is_powerwash_allowed_new_value) {
diff --git a/omaha_request_params.h b/omaha_request_params.h
index 1c0ac0d..8acbc4e 100644
--- a/omaha_request_params.h
+++ b/omaha_request_params.h
@@ -299,7 +299,7 @@
   // Fetches the value for a given key from
   // /mnt/stateful_partition/etc/lsb-release if possible and |stateful_override|
   // is true. Failing that, it looks for the key in /etc/lsb-release. If
-  // |validator| is non-NULL, uses it to validate and ignore invalid values.
+  // |validator| is non-null, uses it to validate and ignore invalid values.
   std::string GetLsbValue(const std::string& key,
                           const std::string& default_value,
                           ValueValidator validator,
diff --git a/omaha_request_params_unittest.cc b/omaha_request_params_unittest.cc
index 432eb6c..1daed1c 100644
--- a/omaha_request_params_unittest.cc
+++ b/omaha_request_params_unittest.cc
@@ -25,7 +25,7 @@
 
  protected:
   // Return true iff the OmahaRequestParams::Init succeeded. If
-  // out is non-NULL, it's set w/ the generated data.
+  // out is non-null, it's set w/ the generated data.
   bool DoTest(OmahaRequestParams* out, const string& app_version,
               const string& omaha_url);
 
diff --git a/omaha_response_handler_action_unittest.cc b/omaha_response_handler_action_unittest.cc
index 51eab78..46ff653 100644
--- a/omaha_response_handler_action_unittest.cc
+++ b/omaha_response_handler_action_unittest.cc
@@ -21,7 +21,7 @@
 class OmahaResponseHandlerActionTest : public ::testing::Test {
  public:
   // Return true iff the OmahaResponseHandlerAction succeeded.
-  // If out is non-NULL, it's set w/ the response from the action.
+  // If out is non-null, it's set w/ the response from the action.
   bool DoTestCommon(FakeSystemState* fake_system_state,
                     const OmahaResponse& in,
                     const string& boot_dev,
@@ -118,7 +118,7 @@
   string test_deadline_file;
   CHECK(utils::MakeTempFile(
           "omaha_response_handler_action_unittest-XXXXXX",
-          &test_deadline_file, NULL));
+          &test_deadline_file, nullptr));
   ScopedPathUnlinker deadline_unlinker(test_deadline_file);
   {
     OmahaResponse in;
diff --git a/p2p_manager.cc b/p2p_manager.cc
index 6d1a773..fcaae1a 100644
--- a/p2p_manager.cc
+++ b/p2p_manager.cc
@@ -135,7 +135,7 @@
   // Utility function used by EnsureP2PRunning() and EnsureP2PNotRunning().
   bool EnsureP2P(bool should_be_running);
 
-  // The device policy being used or NULL if no policy is being used.
+  // The device policy being used or null if no policy is being used.
   const policy::DevicePolicy* device_policy_;
 
   // Configuration object.
@@ -170,11 +170,11 @@
                                PrefsInterface *prefs,
                                const string& file_extension,
                                const int num_files_to_keep)
-  : device_policy_(NULL),
+  : device_policy_(nullptr),
     prefs_(prefs),
     file_extension_(file_extension),
     num_files_to_keep_(num_files_to_keep) {
-  configuration_.reset(configuration != NULL ? configuration :
+  configuration_.reset(configuration != nullptr ? configuration :
                        new ConfigurationImpl());
 }
 
@@ -195,7 +195,7 @@
   //  crosh_flag == TRUE   &&  enterprise_policy == FALSE  -> use_p2p == TRUE
   //  crosh_flag == TRUE   &&  enterprise_policy == TRUE   -> use_p2p == TRUE
 
-  if (device_policy_ != NULL) {
+  if (device_policy_ != nullptr) {
     if (device_policy_->GetAuP2PEnabled(&p2p_enabled)) {
       if (p2p_enabled) {
         LOG(INFO) << "Enterprise Policy indicates that p2p is enabled.";
@@ -204,7 +204,7 @@
     }
   }
 
-  if (prefs_ != NULL &&
+  if (prefs_ != nullptr &&
       prefs_->Exists(kPrefsP2PEnabled) &&
       prefs_->GetBoolean(kPrefsP2PEnabled, &p2p_enabled) &&
       p2p_enabled) {
@@ -218,19 +218,19 @@
 }
 
 bool P2PManagerImpl::EnsureP2P(bool should_be_running) {
-  gchar *standard_error = NULL;
-  GError *error = NULL;
+  gchar *standard_error = nullptr;
+  GError *error = nullptr;
   gint exit_status = 0;
 
   vector<string> args = configuration_->GetInitctlArgs(should_be_running);
   scoped_ptr<gchar*, GLibStrvFreeDeleter> argv(
       utils::StringVectorToGStrv(args));
-  if (!g_spawn_sync(NULL,  // working_directory
+  if (!g_spawn_sync(nullptr,  // working_directory
                     argv.get(),
-                    NULL,  // envp
+                    nullptr,  // envp
                     static_cast<GSpawnFlags>(G_SPAWN_SEARCH_PATH),
-                    NULL, NULL,      // child_setup, user_data
-                    NULL,            // standard_output
+                    nullptr, nullptr,  // child_setup, user_data
+                    nullptr,  // standard_output
                     &standard_error,
                     &exit_status,
                     &error)) {
@@ -307,16 +307,16 @@
 }
 
 bool P2PManagerImpl::PerformHousekeeping() {
-  GDir* dir = NULL;
-  GError* error = NULL;
-  const char* name = NULL;
+  GDir* dir = nullptr;
+  GError* error = nullptr;
+  const char* name = nullptr;
   vector<pair<FilePath, Time> > matches;
 
   // Go through all files in the p2p dir and pick the ones that match
   // and get their ctime.
   base::FilePath p2p_dir = configuration_->GetP2PDir();
   dir = g_dir_open(p2p_dir.value().c_str(), 0, &error);
-  if (dir == NULL) {
+  if (dir == nullptr) {
     LOG(ERROR) << "Error opening directory " << p2p_dir.value() << ": "
                << utils::GetAndFreeGError(&error);
     return false;
@@ -327,7 +327,7 @@
 
   string ext_visible = GetExt(kVisible);
   string ext_non_visible = GetExt(kNonVisible);
-  while ((name = g_dir_read_name(dir)) != NULL) {
+  while ((name = g_dir_read_name(dir)) != nullptr) {
     if (!(g_str_has_suffix(name, ext_visible.c_str()) ||
           g_str_has_suffix(name, ext_non_visible.c_str())))
       continue;
@@ -392,18 +392,18 @@
     // the callback is always called from the GLib mainloop (this
     // guarantee is useful for testing).
 
-    GError *error = NULL;
-    if (!g_spawn_async_with_pipes(NULL,  // working_directory
+    GError *error = nullptr;
+    if (!g_spawn_async_with_pipes(nullptr,  // working_directory
                                   argv,
-                                  NULL,  // envp
+                                  nullptr,  // envp
                                   static_cast<GSpawnFlags>(G_SPAWN_SEARCH_PATH |
                                                      G_SPAWN_DO_NOT_REAP_CHILD),
-                                  NULL,  // child_setup
+                                  nullptr,  // child_setup
                                   this,
                                   &pid_,
-                                  NULL,  // standard_input
+                                  nullptr,  // standard_input
                                   &stdout_fd_,
-                                  NULL,  // standard_error
+                                  nullptr,  // standard_error
                                   &error)) {
       LOG(ERROR) << "Error spawning p2p-client: "
                  << utils::GetAndFreeGError(&error);
@@ -480,12 +480,12 @@
                                       GIOCondition condition,
                                       gpointer user_data) {
     LookupData *lookup_data = reinterpret_cast<LookupData*>(user_data);
-    gchar* str = NULL;
-    GError* error = NULL;
+    gchar* str = nullptr;
+    GError* error = nullptr;
     GIOStatus status = g_io_channel_read_line(source,
                                               &str,
-                                              NULL,  // len
-                                              NULL,  // line_terminator
+                                              nullptr,  // len
+                                              nullptr,  // line_terminator
                                               &error);
     if (status != G_IO_STATUS_NORMAL) {
       // Ignore EOF since we usually get that before SIGCHLD and we
@@ -497,7 +497,7 @@
         delete lookup_data;
       }
     } else {
-      if (str != NULL) {
+      if (str != nullptr) {
         lookup_data->stdout_ += str;
         g_free(str);
       }
@@ -660,7 +660,7 @@
     LOG(ERROR) << "No file for id " << file_id;
     return false;
   }
-  if (out_result != NULL)
+  if (out_result != nullptr)
     *out_result = path.MatchesExtension(kP2PExtension);
   return true;
 }
@@ -716,7 +716,7 @@
     return -1;
   }
 
-  char* endp = NULL;
+  char* endp = nullptr;
   long long int val = strtoll(ea_value, &endp, 0);  // NOLINT(runtime/int)
   if (*endp != '\0') {
     LOG(ERROR) << "Error parsing the value '" << ea_value
@@ -730,13 +730,13 @@
 
 int P2PManagerImpl::CountSharedFiles() {
   GDir* dir;
-  GError* error = NULL;
+  GError* error = nullptr;
   const char* name;
   int num_files = 0;
 
   base::FilePath p2p_dir = configuration_->GetP2PDir();
   dir = g_dir_open(p2p_dir.value().c_str(), 0, &error);
-  if (dir == NULL) {
+  if (dir == nullptr) {
     LOG(ERROR) << "Error opening directory " << p2p_dir.value() << ": "
                << utils::GetAndFreeGError(&error);
     return -1;
@@ -744,7 +744,7 @@
 
   string ext_visible = GetExt(kVisible);
   string ext_non_visible = GetExt(kNonVisible);
-  while ((name = g_dir_read_name(dir)) != NULL) {
+  while ((name = g_dir_read_name(dir)) != nullptr) {
     if (g_str_has_suffix(name, ext_visible.c_str()) ||
         g_str_has_suffix(name, ext_non_visible.c_str())) {
       num_files += 1;
diff --git a/p2p_manager.h b/p2p_manager.h
index 0e6e1b4..b2cb999 100644
--- a/p2p_manager.h
+++ b/p2p_manager.h
@@ -49,7 +49,7 @@
   typedef base::Callback<void(const std::string& url)> LookupCallback;
 
   // Use the device policy specified by |device_policy|. If this is
-  // NULL, then no device policy is used.
+  // null, then no device policy is used.
   virtual void SetDevicePolicy(const policy::DevicePolicy* device_policy) = 0;
 
   // Returns true if - and only if - P2P should be used on this
@@ -133,7 +133,7 @@
   virtual ssize_t FileGetExpectedSize(const std::string& file_id) = 0;
 
   // Gets whether the file identified by |file_id| is publicly
-  // visible. If |out_result| is not NULL, the result is returned
+  // visible. If |out_result| is not null, the result is returned
   // there. Returns false if an error occurs.
   virtual bool FileGetVisible(const std::string& file_id,
                               bool *out_result) = 0;
@@ -152,7 +152,7 @@
   // Creates a suitable P2PManager instance and initializes the object
   // so it's ready for use. The |file_extension| parameter is used to
   // identify your application, use e.g. "cros_au".  If
-  // |configuration| is non-NULL, the P2PManager will take ownership
+  // |configuration| is non-null, the P2PManager will take ownership
   // of the Configuration object and use it (hence, it must be
   // heap-allocated).
   //
diff --git a/p2p_manager_unittest.cc b/p2p_manager_unittest.cc
index eaf66a1..56ba33b 100644
--- a/p2p_manager_unittest.cc
+++ b/p2p_manager_unittest.cc
@@ -142,7 +142,7 @@
 // Check that we keep the $N newest files with the .$EXT.p2p extension.
 TEST_F(P2PManagerTest, Housekeeping) {
   scoped_ptr<P2PManager> manager(P2PManager::Construct(test_conf_,
-                                                       NULL, "cros_au", 3));
+                                                       nullptr, "cros_au", 3));
   EXPECT_EQ(manager->CountSharedFiles(), 0);
 
   // Generate files with different timestamps matching our pattern and generate
@@ -242,9 +242,9 @@
       LOG(ERROR) << "Error getting xattr attribute";
       return false;
     }
-    char* endp = NULL;
+    char* endp = nullptr;
     long long int val = strtoll(ea_value, &endp, 0);  // NOLINT(runtime/int)
-    if (endp == NULL || *endp != '\0') {
+    if (endp == nullptr || *endp != '\0') {
       LOG(ERROR) << "Error parsing xattr '" << ea_value
                  << "' as an integer";
       return false;
@@ -297,7 +297,7 @@
   }
 
   scoped_ptr<P2PManager> manager(P2PManager::Construct(test_conf_,
-                                                       NULL, "cros_au", 3));
+                                                       nullptr, "cros_au", 3));
   EXPECT_TRUE(manager->FileShare("foo", 10 * 1000 * 1000));
   EXPECT_EQ(manager->FileGetPath("foo"),
             test_conf_->GetP2PDir().Append("foo.cros_au.p2p.tmp"));
@@ -320,7 +320,7 @@
   }
 
   scoped_ptr<P2PManager> manager(P2PManager::Construct(test_conf_,
-                                                       NULL, "cros_au", 3));
+                                                       nullptr, "cros_au", 3));
   // First, check that it's not visible.
   manager->FileShare("foo", 10*1000*1000);
   EXPECT_EQ(manager->FileGetPath("foo"),
@@ -347,14 +347,14 @@
   }
 
   scoped_ptr<P2PManager> manager(P2PManager::Construct(test_conf_,
-                                                       NULL, "cros_au", 3));
+                                                       nullptr, "cros_au", 3));
   bool visible;
 
   // Check that errors are returned if the file does not exist
   EXPECT_EQ(manager->FileGetPath("foo"), base::FilePath());
   EXPECT_EQ(manager->FileGetSize("foo"), -1);
   EXPECT_EQ(manager->FileGetExpectedSize("foo"), -1);
-  EXPECT_FALSE(manager->FileGetVisible("foo", NULL));
+  EXPECT_FALSE(manager->FileGetVisible("foo", nullptr));
   // ... then create the file ...
   EXPECT_TRUE(CreateP2PFile(test_conf_->GetP2PDir().value(),
                             "foo.cros_au.p2p", 42, 43));
@@ -370,7 +370,7 @@
   EXPECT_EQ(manager->FileGetPath("bar"), base::FilePath());
   EXPECT_EQ(manager->FileGetSize("bar"), -1);
   EXPECT_EQ(manager->FileGetExpectedSize("bar"), -1);
-  EXPECT_FALSE(manager->FileGetVisible("bar", NULL));
+  EXPECT_FALSE(manager->FileGetVisible("bar", nullptr));
   // ... then create the file ...
   EXPECT_TRUE(CreateP2PFile(test_conf_->GetP2PDir().value(),
                             "bar.cros_au.p2p.tmp", 44, 45));
@@ -388,7 +388,7 @@
 // behaviours of initctl(8) that we rely on.
 TEST_F(P2PManagerTest, StartP2P) {
   scoped_ptr<P2PManager> manager(P2PManager::Construct(test_conf_,
-                                                       NULL, "cros_au", 3));
+                                                       nullptr, "cros_au", 3));
 
   // Check that we can start the service
   test_conf_->SetInitctlStartCommandLine("true");
@@ -406,7 +406,7 @@
 // Same comment as for StartP2P
 TEST_F(P2PManagerTest, StopP2P) {
   scoped_ptr<P2PManager> manager(P2PManager::Construct(test_conf_,
-                                                       NULL, "cros_au", 3));
+                                                       nullptr, "cros_au", 3));
 
   // Check that we can start the service
   test_conf_->SetInitctlStopCommandLine("true");
@@ -432,8 +432,8 @@
 // can return. It's not pretty but it works.
 TEST_F(P2PManagerTest, LookupURL) {
   scoped_ptr<P2PManager> manager(P2PManager::Construct(test_conf_,
-                                                       NULL, "cros_au", 3));
-  GMainLoop *loop = g_main_loop_new(NULL, FALSE);
+                                                       nullptr, "cros_au", 3));
+  GMainLoop *loop = g_main_loop_new(nullptr, FALSE);
 
   // Emulate p2p-client returning valid URL with "fooX", 42 and "cros_au"
   // being propagated in the right places.
diff --git a/payload_generator/delta_diff_generator.cc b/payload_generator/delta_diff_generator.cc
index 1a15f3a..8236292 100644
--- a/payload_generator/delta_diff_generator.cc
+++ b/payload_generator/delta_diff_generator.cc
@@ -105,7 +105,7 @@
 // For a given regular file which must exist at new_root + path, and
 // may exist at old_root + path, creates a new InstallOperation and
 // adds it to the graph. Also, populates the |blocks| array as
-// necessary, if |blocks| is non-NULL.  Also, writes the data
+// necessary, if |blocks| is non-null.  Also, writes the data
 // necessary to send the file down to the client into data_fd, which
 // has length *data_file_size. *data_file_size is updated
 // appropriately. If |existing_vertex| is no kInvalidIndex, use that
@@ -296,7 +296,7 @@
   string temp_file_path;
   TEST_AND_RETURN_FALSE(utils::MakeTempFile("CrAU_temp_data.XXXXXX",
                                             &temp_file_path,
-                                            NULL));
+                                            nullptr));
 
   FILE* file = fopen(temp_file_path.c_str(), "w");
   TEST_AND_RETURN_FALSE(file);
@@ -364,11 +364,11 @@
       }
     }
   }
-  BZ2_bzWriteClose(&err, bz_file, 0, NULL, NULL);
+  BZ2_bzWriteClose(&err, bz_file, 0, nullptr, nullptr);
   TEST_AND_RETURN_FALSE(err == BZ_OK);
-  bz_file = NULL;
+  bz_file = nullptr;
   TEST_AND_RETURN_FALSE_ERRNO(0 == fclose(file));
-  file = NULL;
+  file = nullptr;
 
   vector<char> compressed_data;
   LOG(INFO) << "Reading compressed data off disk";
@@ -1385,7 +1385,7 @@
 
   for (int i = 0; i < (manifest->install_operations_size() +
                        manifest->kernel_install_operations_size()); i++) {
-    DeltaArchiveManifest_InstallOperation* op = NULL;
+    DeltaArchiveManifest_InstallOperation* op = nullptr;
     if (i < manifest->install_operations_size()) {
       op = manifest->mutable_install_operations(i);
     } else {
@@ -1439,7 +1439,7 @@
 
     TEST_AND_RETURN_FALSE(DeltaReadFile(graph,
                                         cut.old_dst,
-                                        NULL,
+                                        nullptr,
                                         kEmptyPath,
                                         new_root,
                                         (*graph)[cut.old_dst].file_name,
@@ -1719,7 +1719,7 @@
   TEST_AND_RETURN_FALSE(utils::MakeTempFile(
       "CrAU_temp_data.ordered.XXXXXX",
       &ordered_blobs_path,
-      NULL));
+      nullptr));
   ScopedPathUnlinker ordered_blobs_unlinker(ordered_blobs_path);
   TEST_AND_RETURN_FALSE(ReorderDataBlobs(&manifest,
                                          temp_file_path,
@@ -1838,7 +1838,7 @@
   string patch_file_path;
 
   TEST_AND_RETURN_FALSE(
-      utils::MakeTempFile(kPatchFile, &patch_file_path, NULL));
+      utils::MakeTempFile(kPatchFile, &patch_file_path, nullptr));
 
   vector<string> cmd;
   cmd.push_back(kBsdiffPath);
@@ -1848,7 +1848,7 @@
 
   int rc = 1;
   vector<char> patch_file;
-  TEST_AND_RETURN_FALSE(Subprocess::SynchronousExec(cmd, &rc, NULL));
+  TEST_AND_RETURN_FALSE(Subprocess::SynchronousExec(cmd, &rc, nullptr));
   TEST_AND_RETURN_FALSE(rc == 0);
   TEST_AND_RETURN_FALSE(utils::ReadFile(patch_file_path, out));
   unlink(patch_file_path.c_str());
diff --git a/payload_generator/delta_diff_generator_unittest.cc b/payload_generator/delta_diff_generator_unittest.cc
index 977b34d..85d041c 100644
--- a/payload_generator/delta_diff_generator_unittest.cc
+++ b/payload_generator/delta_diff_generator_unittest.cc
@@ -64,9 +64,9 @@
 
   virtual void SetUp() {
     ASSERT_TRUE(utils::MakeTempFile("DeltaDiffGeneratorTest-old_path-XXXXXX",
-                                    &old_path_, NULL));
+                                    &old_path_, nullptr));
     ASSERT_TRUE(utils::MakeTempFile("DeltaDiffGeneratorTest-new_path-XXXXXX",
-                                    &new_path_, NULL));
+                                    &new_path_, nullptr));
   }
 
   virtual void TearDown() {
@@ -556,8 +556,8 @@
 
 TEST_F(DeltaDiffGeneratorTest, ReorderBlobsTest) {
   string orig_blobs;
-  EXPECT_TRUE(
-      utils::MakeTempFile("ReorderBlobsTest.orig.XXXXXX", &orig_blobs, NULL));
+  EXPECT_TRUE(utils::MakeTempFile("ReorderBlobsTest.orig.XXXXXX", &orig_blobs,
+                                  nullptr));
 
   string orig_data = "abcd";
   EXPECT_TRUE(
@@ -565,7 +565,7 @@
 
   string new_blobs;
   EXPECT_TRUE(
-      utils::MakeTempFile("ReorderBlobsTest.new.XXXXXX", &new_blobs, NULL));
+      utils::MakeTempFile("ReorderBlobsTest.new.XXXXXX", &new_blobs, nullptr));
 
   DeltaArchiveManifest manifest;
   DeltaArchiveManifest_InstallOperation* op =
@@ -718,7 +718,7 @@
 
   int fd;
   EXPECT_TRUE(utils::MakeTempFile("AssignTempBlocksTestData.XXXXXX",
-                                  NULL,
+                                  nullptr,
                                   &fd));
   ScopedFdCloser fd_closer(&fd);
   off_t data_file_size = 0;
@@ -835,7 +835,7 @@
 
   int fd = -1;
   EXPECT_TRUE(utils::MakeTempFile("NoSparseAsTempTestData.XXXXXX",
-                                  NULL,
+                                  nullptr,
                                   &fd));
   ScopedFdCloser fd_closer(&fd);
   off_t data_file_size = 0;
@@ -1096,7 +1096,7 @@
 
   int fd;
   EXPECT_TRUE(utils::MakeTempFile("AssignTempBlocksReuseTest.XXXXXX",
-                                  NULL,
+                                  nullptr,
                                   &fd));
   ScopedFdCloser fd_closer(&fd);
   off_t data_file_size = 0;
diff --git a/payload_generator/filesystem_iterator_unittest.cc b/payload_generator/filesystem_iterator_unittest.cc
index 7436c99..047c8a4 100644
--- a/payload_generator/filesystem_iterator_unittest.cc
+++ b/payload_generator/filesystem_iterator_unittest.cc
@@ -52,12 +52,12 @@
   // Create uniquely named main/sub images.
   string main_image;
   ASSERT_TRUE(utils::MakeTempFile("FilesystemIteratorTest.image1-XXXXXX",
-                                  &main_image, NULL));
+                                  &main_image, nullptr));
   ScopedPathUnlinker main_image_unlinker(main_image);
 
   string sub_image;
   ASSERT_TRUE(utils::MakeTempFile("FilesystemIteratorTest.image2-XXXXXX",
-                                  &sub_image, NULL));
+                                  &sub_image, nullptr));
   ScopedPathUnlinker sub_image_unlinker(sub_image);
 
   // Create uniquely named main/sub mount points.
@@ -70,7 +70,7 @@
 
   vector<string> expected_paths_vector;
   CreateExtImageAtPath(main_image, &expected_paths_vector);
-  CreateExtImageAtPath(sub_image, NULL);
+  CreateExtImageAtPath(sub_image, nullptr);
   ASSERT_EQ(0, System(string("mount -o loop ") + main_image + " " +
                       main_image_mount_point));
   ASSERT_EQ(0, System(string("mount -o loop ") + sub_image + " " +
diff --git a/payload_generator/full_update_generator.cc b/payload_generator/full_update_generator.cc
index d4d6614..5b6a6b3 100644
--- a/payload_generator/full_update_generator.cc
+++ b/payload_generator/full_update_generator.cc
@@ -35,7 +35,7 @@
  public:
   // Read a chunk of |size| bytes from |fd| starting at offset |offset|.
   ChunkProcessor(int fd, off_t offset, size_t size)
-      : thread_(NULL),
+      : thread_(nullptr),
         fd_(fd),
         offset_(offset),
         buffer_in_(size) {}
@@ -74,8 +74,9 @@
 bool ChunkProcessor::Start() {
   // g_thread_create is deprecated since glib 2.32. Use
   // g_thread_new instead.
-  thread_ = g_thread_try_new("chunk_proc", ReadAndCompressThread, this, NULL);
-  TEST_AND_RETURN_FALSE(thread_ != NULL);
+  thread_ = g_thread_try_new("chunk_proc", ReadAndCompressThread, this,
+                             nullptr);
+  TEST_AND_RETURN_FALSE(thread_ != nullptr);
   return true;
 }
 
@@ -84,14 +85,14 @@
     return false;
   }
   gpointer result = g_thread_join(thread_);
-  thread_ = NULL;
+  thread_ = nullptr;
   TEST_AND_RETURN_FALSE(result == this);
   return true;
 }
 
 gpointer ChunkProcessor::ReadAndCompressThread(gpointer data) {
-  return
-      reinterpret_cast<ChunkProcessor*>(data)->ReadAndCompress() ? data : NULL;
+  return reinterpret_cast<ChunkProcessor*>(data)->ReadAndCompress() ?
+      data : nullptr;
 }
 
 bool ChunkProcessor::ReadAndCompress() {
@@ -161,7 +162,7 @@
       threads.pop_front();
       TEST_AND_RETURN_FALSE(processor->Wait());
 
-      DeltaArchiveManifest_InstallOperation* op = NULL;
+      DeltaArchiveManifest_InstallOperation* op = nullptr;
       if (partition == 0) {
         graph->resize(graph->size() + 1);
         graph->back().file_name =
diff --git a/payload_generator/full_update_generator_unittest.cc b/payload_generator/full_update_generator_unittest.cc
index 689c5ce..7cb2d7a 100644
--- a/payload_generator/full_update_generator_unittest.cc
+++ b/payload_generator/full_update_generator_unittest.cc
@@ -35,14 +35,14 @@
   string new_root_path;
   EXPECT_TRUE(utils::MakeTempFile("NewFullUpdateTest_R.XXXXXX",
                                   &new_root_path,
-                                  NULL));
+                                  nullptr));
   ScopedPathUnlinker new_root_path_unlinker(new_root_path);
   EXPECT_TRUE(WriteFileVector(new_root_path, new_root));
 
   string new_kern_path;
   EXPECT_TRUE(utils::MakeTempFile("NewFullUpdateTest_K.XXXXXX",
                                   &new_kern_path,
-                                  NULL));
+                                  nullptr));
   ScopedPathUnlinker new_kern_path_unlinker(new_kern_path);
   EXPECT_TRUE(WriteFileVector(new_kern_path, new_kern));
 
diff --git a/payload_generator/generate_delta_main.cc b/payload_generator/generate_delta_main.cc
index a2b6b3c..38c4e76 100644
--- a/payload_generator/generate_delta_main.cc
+++ b/payload_generator/generate_delta_main.cc
@@ -264,7 +264,7 @@
                                   kern_info.hash().end());
   install_plan.rootfs_hash.assign(root_info.hash().begin(),
                                   root_info.hash().end());
-  DeltaPerformer performer(&prefs, NULL, &install_plan);
+  DeltaPerformer performer(&prefs, nullptr, &install_plan);
   CHECK_EQ(performer.Open(FLAGS_old_image.c_str(), 0, 0), 0);
   CHECK(performer.OpenKernel(FLAGS_old_kernel.c_str()));
   vector<char> buf(1024 * 1024);
@@ -378,7 +378,7 @@
       FLAGS_private_key,
       FLAGS_chunk_size,
       FLAGS_rootfs_partition_size,
-      is_delta ? &old_image_info : NULL,
+      is_delta ? &old_image_info : nullptr,
       &new_image_info,
       &metadata_size)) {
     return 1;
diff --git a/payload_generator/metadata.cc b/payload_generator/metadata.cc
index 7ed1727..460aa46 100644
--- a/payload_generator/metadata.cc
+++ b/payload_generator/metadata.cc
@@ -359,7 +359,7 @@
     bool all_blocks = ((ino == EXT2_JOURNAL_INO) || is_old_dir || is_new_dir);
 
     vector<Extent> old_extents;
-    error = ext2fs_block_iterate2(fs_old, ino, 0, NULL,
+    error = ext2fs_block_iterate2(fs_old, ino, 0, nullptr,
                                   all_blocks ? ProcessInodeAllBlocks :
                                                ProcessInodeMetadataBlocks,
                                   &old_extents);
@@ -370,7 +370,7 @@
     }
 
     vector<Extent> new_extents;
-    error = ext2fs_block_iterate2(fs_new, ino, 0, NULL,
+    error = ext2fs_block_iterate2(fs_new, ino, 0, nullptr,
                                   all_blocks ? ProcessInodeAllBlocks :
                                                ProcessInodeMetadataBlocks,
                                   &new_extents);
diff --git a/payload_generator/metadata_unittest.cc b/payload_generator/metadata_unittest.cc
index dcce0c3..93b0917 100644
--- a/payload_generator/metadata_unittest.cc
+++ b/payload_generator/metadata_unittest.cc
@@ -32,9 +32,9 @@
 
 TEST_F(MetadataTest, RunAsRootReadMetadataDissimilarFileSystems) {
   string a_img, b_img;
-  EXPECT_TRUE(utils::MakeTempFile("a_img.XXXXXX", &a_img, NULL));
+  EXPECT_TRUE(utils::MakeTempFile("a_img.XXXXXX", &a_img, nullptr));
   ScopedPathUnlinker a_img_unlinker(a_img);
-  EXPECT_TRUE(utils::MakeTempFile("b_img.XXXXXX", &b_img, NULL));
+  EXPECT_TRUE(utils::MakeTempFile("b_img.XXXXXX", &b_img, nullptr));
   ScopedPathUnlinker b_img_unlinker(b_img);
 
   CreateEmptyExtImageAtPath(a_img, 10485759, 4096);
@@ -47,7 +47,7 @@
                                           a_img,
                                           b_img,
                                           0,
-                                          NULL));
+                                          nullptr));
   EXPECT_EQ(graph.size(), 0);
 
   CreateEmptyExtImageAtPath(a_img, 10485759, 4096);
@@ -60,17 +60,17 @@
                                           a_img,
                                           b_img,
                                           0,
-                                          NULL));
+                                          nullptr));
   EXPECT_EQ(graph.size(), 0);
 }
 
 TEST_F(MetadataTest, RunAsRootReadMetadata) {
   string a_img, b_img, data_file;
-  EXPECT_TRUE(utils::MakeTempFile("a_img.XXXXXX", &a_img, NULL));
+  EXPECT_TRUE(utils::MakeTempFile("a_img.XXXXXX", &a_img, nullptr));
   ScopedPathUnlinker a_img_unlinker(a_img);
-  EXPECT_TRUE(utils::MakeTempFile("b_img.XXXXXX", &b_img, NULL));
+  EXPECT_TRUE(utils::MakeTempFile("b_img.XXXXXX", &b_img, nullptr));
   ScopedPathUnlinker b_img_unlinker(b_img);
-  EXPECT_TRUE(utils::MakeTempFile("data_file.XXXXXX", &data_file, NULL));
+  EXPECT_TRUE(utils::MakeTempFile("data_file.XXXXXX", &data_file, nullptr));
   ScopedPathUnlinker data_file_unlinker(data_file);
 
   const size_t image_size = (256 * 1024 * 1024);  // Enough for 2 block groups
diff --git a/payload_generator/payload_signer.cc b/payload_generator/payload_signer.cc
index 4bbb155..9a9008f 100644
--- a/payload_generator/payload_signer.cc
+++ b/payload_generator/payload_signer.cc
@@ -128,12 +128,12 @@
   LOG(INFO) << "Signing hash with private key: " << private_key_path;
   string sig_path;
   TEST_AND_RETURN_FALSE(
-      utils::MakeTempFile("signature.XXXXXX", &sig_path, NULL));
+      utils::MakeTempFile("signature.XXXXXX", &sig_path, nullptr));
   ScopedPathUnlinker sig_path_unlinker(sig_path);
 
   string hash_path;
   TEST_AND_RETURN_FALSE(
-      utils::MakeTempFile("hash.XXXXXX", &hash_path, NULL));
+      utils::MakeTempFile("hash.XXXXXX", &hash_path, nullptr));
   ScopedPathUnlinker hash_path_unlinker(hash_path);
   // We expect unpadded SHA256 hash coming in
   TEST_AND_RETURN_FALSE(hash.size() == 32);
@@ -158,7 +158,8 @@
   cmd[0] = utils::GetPathOnBoard("openssl");
 
   int return_code = 0;
-  TEST_AND_RETURN_FALSE(Subprocess::SynchronousExec(cmd, &return_code, NULL));
+  TEST_AND_RETURN_FALSE(Subprocess::SynchronousExec(cmd, &return_code,
+                                                    nullptr));
   TEST_AND_RETURN_FALSE(return_code == 0);
 
   vector<char> signature;
@@ -193,7 +194,7 @@
 
   string x_path;
   TEST_AND_RETURN_FALSE(
-      utils::MakeTempFile("signed_data.XXXXXX", &x_path, NULL));
+      utils::MakeTempFile("signed_data.XXXXXX", &x_path, nullptr));
   ScopedPathUnlinker x_path_unlinker(x_path);
   TEST_AND_RETURN_FALSE(utils::WriteFile(x_path.c_str(), "x", 1));
 
diff --git a/payload_generator/payload_signer_unittest.cc b/payload_generator/payload_signer_unittest.cc
index 00df88c..c2cd209 100644
--- a/payload_generator/payload_signer_unittest.cc
+++ b/payload_generator/payload_signer_unittest.cc
@@ -85,7 +85,7 @@
 void SignSampleData(vector<char>* out_signature_blob) {
   string data_path;
   ASSERT_TRUE(
-      utils::MakeTempFile("data.XXXXXX", &data_path, NULL));
+      utils::MakeTempFile("data.XXXXXX", &data_path, nullptr));
   ScopedPathUnlinker data_path_unlinker(data_path);
   ASSERT_TRUE(utils::WriteFile(data_path.c_str(),
                                kDataToSign,
diff --git a/payload_state.cc b/payload_state.cc
index 1dd2ee6..b58f9a8 100644
--- a/payload_state.cc
+++ b/payload_state.cc
@@ -39,7 +39,7 @@
 static const uint32_t kMaxBackoffFuzzMinutes = 12 * 60;
 
 PayloadState::PayloadState()
-    : prefs_(NULL),
+    : prefs_(nullptr),
       using_p2p_for_downloading_(false),
       payload_attempt_number_(0),
       full_payload_attempt_number_(0),
diff --git a/payload_verifier.cc b/payload_verifier.cc
index c4bf912..91cb42a 100644
--- a/payload_verifier.cc
+++ b/payload_verifier.cc
@@ -87,7 +87,7 @@
   LOG(INFO) << "Payload size: " << payload.size();
   ErrorCode error = ErrorCode::kSuccess;
   InstallPlan install_plan;
-  DeltaPerformer delta_performer(NULL, NULL, &install_plan);
+  DeltaPerformer delta_performer(nullptr, nullptr, &install_plan);
   TEST_AND_RETURN_FALSE(
       delta_performer.ParsePayloadMetadata(payload, &error) ==
       DeltaPerformer::kMetadataParseSuccess);
@@ -154,9 +154,9 @@
   }
 
   char dummy_password[] = { ' ', 0 };  // Ensure no password is read from stdin.
-  RSA* rsa = PEM_read_RSA_PUBKEY(fpubkey, NULL, NULL, dummy_password);
+  RSA* rsa = PEM_read_RSA_PUBKEY(fpubkey, nullptr, nullptr, dummy_password);
   fclose(fpubkey);
-  TEST_AND_RETURN_FALSE(rsa != NULL);
+  TEST_AND_RETURN_FALSE(rsa != nullptr);
   unsigned int keysize = RSA_size(rsa);
   if (sig_data.size() > 2 * keysize) {
     LOG(ERROR) << "Signature size is too big for public key size.";
diff --git a/postinstall_runner_action.cc b/postinstall_runner_action.cc
index 562ba16..81e546e 100644
--- a/postinstall_runner_action.cc
+++ b/postinstall_runner_action.cc
@@ -43,7 +43,7 @@
                  temp_rootfs_dir_.c_str(),
                  "ext2",
                  mountflags,
-                 NULL);
+                 nullptr);
   // TODO(sosa): Remove once crbug.com/208022 is resolved.
   if (rc < 0) {
     LOG(INFO) << "Failed to mount install part "
@@ -52,7 +52,7 @@
                temp_rootfs_dir_.c_str(),
                "ext3",
                mountflags,
-               NULL);
+               nullptr);
   }
   if (rc < 0) {
     LOG(ERROR) << "Unable to mount destination device " << install_device
diff --git a/postinstall_runner_action.h b/postinstall_runner_action.h
index ee7c0b8..e7ac1c5 100644
--- a/postinstall_runner_action.h
+++ b/postinstall_runner_action.h
@@ -19,7 +19,7 @@
  public:
   PostinstallRunnerAction()
       : powerwash_marker_created_(false),
-        powerwash_marker_file_(NULL) {}
+        powerwash_marker_file_(nullptr) {}
 
   void PerformAction();
 
@@ -44,8 +44,8 @@
   // False otherwise. Used for cleaning up if post-install fails.
   bool powerwash_marker_created_;
 
-  // Non-NULL value will cause post-install to override the default marker file
-  // name; used for testing.
+  // Non-null value will cause post-install to override the default marker
+  // file name; used for testing.
   const char* powerwash_marker_file_;
 
   // Special ctor + friend declaration for testing purposes.
diff --git a/postinstall_runner_action_unittest.cc b/postinstall_runner_action_unittest.cc
index acceb2b..d5e795e 100644
--- a/postinstall_runner_action_unittest.cc
+++ b/postinstall_runner_action_unittest.cc
@@ -46,7 +46,7 @@
 class PostinstActionProcessorDelegate : public ActionProcessorDelegate {
  public:
   PostinstActionProcessorDelegate()
-      : loop_(NULL),
+      : loop_(nullptr),
         code_(ErrorCode::kError),
         code_set_(false) {}
   void ProcessingDone(const ActionProcessor* processor,
@@ -218,7 +218,7 @@
     ASSERT_LT(rc, 0);
 
   if (do_losetup) {
-    loop_releaser.reset(NULL);
+    loop_releaser.reset(nullptr);
   }
 
   // Remove unique stateful directory.
diff --git a/real_system_state.cc b/real_system_state.cc
index 44ff5fb..f093aad 100644
--- a/real_system_state.cc
+++ b/real_system_state.cc
@@ -41,7 +41,7 @@
     system_rebooted_ = true;
   }
 
-  p2p_manager_.reset(P2PManager::Construct(NULL, &prefs_, "cros_au",
+  p2p_manager_.reset(P2PManager::Construct(nullptr, &prefs_, "cros_au",
                                            kMaxP2PFilesToKeep));
 
   // Initialize the Update Manager using the default state factory.
diff --git a/subprocess.cc b/subprocess.cc
index aab71b5..e2ab793 100644
--- a/subprocess.cc
+++ b/subprocess.cc
@@ -65,7 +65,7 @@
                                  buf,
                                  arraysize(buf),
                                  &bytes_read,
-                                 NULL) == G_IO_STATUS_NORMAL &&
+                                 nullptr) == G_IO_STATUS_NORMAL &&
          bytes_read > 0) {
     stdout->append(buf, bytes_read);
   }
@@ -76,7 +76,7 @@
 void FreeArgv(char** argv) {
   for (int i = 0; argv[i]; i++) {
     free(argv[i]);
-    argv[i] = NULL;
+    argv[i] = nullptr;
   }
 }
 
@@ -86,7 +86,7 @@
 }
 
 // Note: Caller responsible for free()ing the returned value!
-// Will return NULL on failure and free any allocated memory.
+// Will return null on failure and free any allocated memory.
 char** ArgPointer() {
   const char* keys[] = {"LD_LIBRARY_PATH", "PATH"};
   char** ret = new char*[arraysize(keys) + 1];
@@ -98,12 +98,12 @@
       if (!ret[pointer]) {
         FreeArgv(ret);
         delete [] ret;
-        return NULL;
+        return nullptr;
       }
       ++pointer;
     }
   }
-  ret[pointer] = NULL;
+  ret[pointer] = nullptr;
   return ret;
 }
 
@@ -131,15 +131,15 @@
   for (unsigned int i = 0; i < cmd.size(); i++) {
     argv[i] = strdup(cmd[i].c_str());
     if (!argv[i]) {
-      FreeArgvInError(argv.get());  // NULL in argv[i] terminates argv.
+      FreeArgvInError(argv.get());  // null in argv[i] terminates argv.
       return 0;
     }
   }
-  argv[cmd.size()] = NULL;
+  argv[cmd.size()] = nullptr;
 
   char** argp = ArgPointer();
   if (!argp) {
-    FreeArgvInError(argv.get());  // NULL in argv[i] terminates argv.
+    FreeArgvInError(argv.get());  // null in argv[i] terminates argv.
     return 0;
   }
   ScopedFreeArgPointer argp_free(argp);
@@ -150,16 +150,16 @@
   gint stdout_fd = -1;
   GError* error = nullptr;
   bool success = g_spawn_async_with_pipes(
-      NULL,  // working directory
+      nullptr,  // working directory
       argv.get(),
       argp,
       G_SPAWN_DO_NOT_REAP_CHILD,  // flags
       GRedirectStderrToStdout,  // child setup function
-      NULL,  // child setup data pointer
+      nullptr,  // child setup data pointer
       &child_pid,
-      NULL,
+      nullptr,
       &stdout_fd,
-      NULL,
+      nullptr,
       &error);
   FreeArgv(argv.get());
   if (!success) {
@@ -172,9 +172,9 @@
 
   // Capture the subprocess output.
   record->gioout = g_io_channel_unix_new(stdout_fd);
-  g_io_channel_set_encoding(record->gioout, NULL, NULL);
+  g_io_channel_set_encoding(record->gioout, nullptr, nullptr);
   LOG_IF(WARNING,
-         g_io_channel_set_flags(record->gioout, G_IO_FLAG_NONBLOCK, NULL) !=
+         g_io_channel_set_flags(record->gioout, G_IO_FLAG_NONBLOCK, nullptr) !=
          G_IO_STATUS_NORMAL) << "Unable to set non-blocking I/O mode.";
   record->gioout_tag = g_io_add_watch(
       record->gioout,
@@ -185,7 +185,7 @@
 }
 
 void Subprocess::CancelExec(uint32_t tag) {
-  subprocess_records_[tag]->callback = NULL;
+  subprocess_records_[tag]->callback = nullptr;
 }
 
 bool Subprocess::SynchronousExecFlags(const vector<string>& cmd,
@@ -195,35 +195,35 @@
   if (stdout) {
     *stdout = "";
   }
-  GError* err = NULL;
+  GError* err = nullptr;
   scoped_ptr<char*[]> argv(new char*[cmd.size() + 1]);
   for (unsigned int i = 0; i < cmd.size(); i++) {
     argv[i] = strdup(cmd[i].c_str());
     if (!argv[i]) {
-      FreeArgvInError(argv.get());  // NULL in argv[i] terminates argv.
+      FreeArgvInError(argv.get());  // null in argv[i] terminates argv.
       return false;
     }
   }
-  argv[cmd.size()] = NULL;
+  argv[cmd.size()] = nullptr;
 
   char** argp = ArgPointer();
   if (!argp) {
-    FreeArgvInError(argv.get());  // NULL in argv[i] terminates argv.
+    FreeArgvInError(argv.get());  // null in argv[i] terminates argv.
     return false;
   }
   ScopedFreeArgPointer argp_free(argp);
 
   char* child_stdout;
   bool success = g_spawn_sync(
-      NULL,  // working directory
+      nullptr,  // working directory
       argv.get(),
       argp,
       static_cast<GSpawnFlags>(G_SPAWN_STDERR_TO_DEV_NULL |
                                G_SPAWN_SEARCH_PATH | flags),  // flags
       GRedirectStderrToStdout,  // child setup function
-      NULL,  // data for child setup function
+      nullptr,  // data for child setup function
       &child_stdout,
-      NULL,
+      nullptr,
       return_code,
       &err);
   FreeArgv(argv.get());
@@ -258,6 +258,6 @@
   return false;
 }
 
-Subprocess* Subprocess::subprocess_singleton_ = NULL;
+Subprocess* Subprocess::subprocess_singleton_ = nullptr;
 
 }  // namespace chromeos_update_engine
diff --git a/subprocess.h b/subprocess.h
index 4311595..4279321 100644
--- a/subprocess.h
+++ b/subprocess.h
@@ -64,9 +64,9 @@
   struct SubprocessRecord {
     SubprocessRecord()
         : tag(0),
-          callback(NULL),
-          callback_data(NULL),
-          gioout(NULL),
+          callback(nullptr),
+          callback_data(nullptr),
+          gioout(nullptr),
           gioout_tag(0) {}
     uint32_t tag;
     ExecCallback callback;
diff --git a/subprocess_unittest.cc b/subprocess_unittest.cc
index 7c25075..9ef3e0b 100644
--- a/subprocess_unittest.cc
+++ b/subprocess_unittest.cc
@@ -101,7 +101,7 @@
   cmd.push_back("-c");
   cmd.push_back("echo test");
   int rc = -1;
-  ASSERT_TRUE(Subprocess::SynchronousExec(cmd, &rc, NULL));
+  ASSERT_TRUE(Subprocess::SynchronousExec(cmd, &rc, nullptr));
   EXPECT_EQ(0, rc);
 }
 
@@ -136,7 +136,7 @@
   vector<string> cmd;
   cmd.push_back("./test_http_server");
   cmd.push_back(temp_file_name);
-  uint32_t tag = Subprocess::Get().Exec(cmd, CallbackBad, NULL);
+  uint32_t tag = Subprocess::Get().Exec(cmd, CallbackBad, nullptr);
   EXPECT_NE(0, tag);
   cancel_test_data->spawned = true;
   printf("test http server spawned\n");
diff --git a/test_http_server.cc b/test_http_server.cc
index f5f9202..2687d99 100644
--- a/test_http_server.cc
+++ b/test_http_server.cc
@@ -604,7 +604,7 @@
 
   while (1) {
     LOG(INFO) << "pid(" << getpid() <<  "): waiting to accept new connection";
-    int client_fd = accept(listen_fd, NULL, NULL);
+    int client_fd = accept(listen_fd, nullptr, nullptr);
     LOG(INFO) << "got past accept";
     if (client_fd < 0)
       LOG(FATAL) << "ERROR on accept";
diff --git a/test_utils.cc b/test_utils.cc
index b452ca3..70eb35c 100644
--- a/test_utils.cc
+++ b/test_utils.cc
@@ -319,7 +319,7 @@
 }
 
 void RunGMainLoopUntil(int timeout_msec, base::Callback<bool()> terminate) {
-  GMainLoop* loop = g_main_loop_new(NULL, FALSE);
+  GMainLoop* loop = g_main_loop_new(nullptr, FALSE);
   GMainContext* context = g_main_context_default();
 
   bool timeout = false;
diff --git a/test_utils.h b/test_utils.h
index e81eabd..45f409c 100644
--- a/test_utils.h
+++ b/test_utils.h
@@ -153,7 +153,7 @@
       args.push_back("-d");
       args.push_back(dev_);
       int return_code = 0;
-      EXPECT_TRUE(Subprocess::SynchronousExec(args, &return_code, NULL));
+      EXPECT_TRUE(Subprocess::SynchronousExec(args, &return_code, nullptr));
       if (return_code == 0) {
         return;
       }
@@ -180,7 +180,7 @@
   ScopedTempFile() {
     EXPECT_TRUE(utils::MakeTempFile("/tmp/update_engine_test_temp_file.XXXXXX",
                                     &path_,
-                                    NULL));
+                                    nullptr));
     unlinker_.reset(new ScopedPathUnlinker(path_));
   }
   const std::string& GetPath() { return path_; }
diff --git a/update_attempter.cc b/update_attempter.cc
index d0ef575..c6f1588 100644
--- a/update_attempter.cc
+++ b/update_attempter.cc
@@ -188,7 +188,7 @@
 void UpdateAttempter::ReportOSAge() {
   struct stat sb;
 
-  if (system_state_ == NULL)
+  if (system_state_ == nullptr)
     return;
 
   if (stat("/etc/lsb-release", &sb) != 0) {
@@ -278,7 +278,7 @@
     policy_provider_.reset(new policy::PolicyProvider());
   policy_provider_->Reload();
 
-  const policy::DevicePolicy* device_policy = NULL;
+  const policy::DevicePolicy* device_policy = nullptr;
   if (policy_provider_->device_policy_is_loaded())
     device_policy = &policy_provider_->GetDevicePolicy();
 
@@ -302,7 +302,7 @@
   // update_engine or p2p codebases so he can actually test his
   // code.).
 
-  if (system_state_ != NULL) {
+  if (system_state_ != nullptr) {
     if (!system_state_->p2p_manager()->IsP2PEnabled()) {
       LOG(INFO) << "p2p is not enabled - disallowing p2p for both"
                 << " downloading and sharing.";
@@ -587,7 +587,7 @@
   update_check_fetcher->set_check_certificate(CertificateChecker::kUpdate);
   shared_ptr<OmahaRequestAction> update_check_action(
       new OmahaRequestAction(system_state_,
-                             NULL,
+                             nullptr,
                              update_check_fetcher,  // passes ownership
                              false));
   shared_ptr<OmahaResponseHandlerAction> response_handler_action(
@@ -846,7 +846,7 @@
 }
 
 bool UpdateAttempter::RequestPowerManagerReboot() {
-  GError* error = NULL;
+  GError* error = nullptr;
   DBusGConnection* bus = dbus_iface_->BusGet(DBUS_BUS_SYSTEM, &error);
   if (!bus) {
     LOG(ERROR) << "Failed to get system bus: "
@@ -884,7 +884,7 @@
   command.push_back("now");
   LOG(INFO) << "Running \"" << JoinString(command, ' ') << "\"";
   int rc = 0;
-  Subprocess::SynchronousExec(command, &rc, NULL);
+  Subprocess::SynchronousExec(command, &rc, nullptr);
   return rc == 0;
 }
 
@@ -935,8 +935,8 @@
     SetStatusAndNotify(UPDATE_STATUS_UPDATED_NEED_REBOOT);
     LOG(INFO) << "Update successfully applied, waiting to reboot.";
 
-    // This pointer is NULL during rollback operations, and the stats
-    // don't make much sense then anway.
+    // This pointer is null during rollback operations, and the stats
+    // don't make much sense then anyway.
     if (response_handler_action_) {
       const InstallPlan& install_plan =
           response_handler_action_->install_plan();
@@ -977,7 +977,7 @@
   download_progress_ = 0.0;
   SetStatusAndNotify(UPDATE_STATUS_IDLE);
   actions_.clear();
-  error_event_.reset(NULL);
+  error_event_.reset(nullptr);
 }
 
 // Called whenever an action has finished processing, either successfully
@@ -1039,7 +1039,7 @@
     // cases when the server and the client are unable to initiate the download.
     CHECK(action == response_handler_action_.get());
     const InstallPlan& plan = response_handler_action_->install_plan();
-    last_checked_time_ = time(NULL);
+    last_checked_time_ = time(nullptr);
     new_version_ = plan.version;
     new_payload_size_ = plan.payload_size;
     SetupDownload();
@@ -1276,7 +1276,7 @@
 }
 
 bool UpdateAttempter::ScheduleErrorEventAction() {
-  if (error_event_.get() == NULL)
+  if (error_event_.get() == nullptr)
     return false;
 
   LOG(ERROR) << "Update failed.";
@@ -1320,15 +1320,15 @@
   g_source_set_callback(manage_shares_source_,
                         StaticManageCpuSharesCallback,
                         this,
-                        NULL);
-  g_source_attach(manage_shares_source_, NULL);
+                        nullptr);
+  g_source_attach(manage_shares_source_, nullptr);
   SetCpuShares(utils::kCpuSharesLow);
 }
 
 void UpdateAttempter::CleanupCpuSharesManagement() {
   if (manage_shares_source_) {
     g_source_destroy(manage_shares_source_);
-    manage_shares_source_ = NULL;
+    manage_shares_source_ = nullptr;
   }
   SetCpuShares(utils::kCpuSharesNormal);
 }
@@ -1350,7 +1350,7 @@
 
 bool UpdateAttempter::ManageCpuSharesCallback() {
   SetCpuShares(utils::kCpuSharesNormal);
-  manage_shares_source_ = NULL;
+  manage_shares_source_ = nullptr;
   return false;  // Destroy the timeout source.
 }
 
@@ -1402,12 +1402,12 @@
   if (!processor_->IsRunning()) {
     shared_ptr<OmahaRequestAction> ping_action(
         new OmahaRequestAction(system_state_,
-                               NULL,
+                               nullptr,
                                new LibcurlHttpFetcher(GetProxyResolver(),
                                                       system_state_),
                                true));
     actions_.push_back(shared_ptr<OmahaRequestAction>(ping_action));
-    processor_->set_delegate(NULL);
+    processor_->set_delegate(nullptr);
     processor_->EnqueueAction(ping_action.get());
     // Call StartProcessing() synchronously here to avoid any race conditions
     // caused by multiple outstanding ping Omaha requests.  If we call
@@ -1481,7 +1481,7 @@
 void UpdateAttempter::UpdateEngineStarted() {
   // If we just booted into a new update, keep the previous OS version
   // in case we rebooted because of a crash of the old version, so we
-  // can do a proper crash report with correcy information.
+  // can do a proper crash report with correct information.
   // This must be done before calling
   // system_state_->payload_state()->UpdateEngineStarted() since it will
   // delete SystemUpdated marker file.
@@ -1498,7 +1498,7 @@
 }
 
 bool UpdateAttempter::StartP2PAtStartup() {
-  if (system_state_ == NULL ||
+  if (system_state_ == nullptr ||
       !system_state_->p2p_manager()->IsP2PEnabled()) {
     LOG(INFO) << "Not starting p2p at startup since it's not enabled.";
     return false;
@@ -1514,7 +1514,7 @@
 }
 
 bool UpdateAttempter::StartP2PAndPerformHousekeeping() {
-  if (system_state_ == NULL)
+  if (system_state_ == nullptr)
     return false;
 
   if (!system_state_->p2p_manager()->IsP2PEnabled()) {
diff --git a/update_attempter_unittest.cc b/update_attempter_unittest.cc
index c9ff687..765d71d 100644
--- a/update_attempter_unittest.cc
+++ b/update_attempter_unittest.cc
@@ -64,7 +64,7 @@
   UpdateAttempterTest()
       : attempter_(&fake_system_state_, &dbus_),
         mock_connection_manager(&fake_system_state_),
-        loop_(NULL) {
+        loop_(nullptr) {
     // Override system state members.
     fake_system_state_.set_connection_manager(&mock_connection_manager);
     fake_system_state_.set_update_attempter(&attempter_);
@@ -82,12 +82,12 @@
   virtual void SetUp() {
     CHECK(utils::MakeTempDirectory("UpdateAttempterTest-XXXXXX", &test_dir_));
 
-    EXPECT_EQ(NULL, attempter_.dbus_service_);
-    EXPECT_TRUE(attempter_.system_state_ != NULL);
-    EXPECT_EQ(NULL, attempter_.update_check_scheduler_);
+    EXPECT_EQ(nullptr, attempter_.dbus_service_);
+    EXPECT_NE(nullptr, attempter_.system_state_);
+    EXPECT_EQ(nullptr, attempter_.update_check_scheduler_);
     EXPECT_EQ(0, attempter_.http_response_code_);
     EXPECT_EQ(utils::kCpuSharesNormal, attempter_.shares_);
-    EXPECT_EQ(NULL, attempter_.manage_shares_source_);
+    EXPECT_EQ(nullptr, attempter_.manage_shares_source_);
     EXPECT_FALSE(attempter_.download_active_);
     EXPECT_EQ(UPDATE_STATUS_IDLE, attempter_.status_);
     EXPECT_EQ(0.0, attempter_.download_progress_);
@@ -170,14 +170,14 @@
 };
 
 TEST_F(UpdateAttempterTest, ActionCompletedDownloadTest) {
-  scoped_ptr<MockHttpFetcher> fetcher(new MockHttpFetcher("", 0, NULL));
+  scoped_ptr<MockHttpFetcher> fetcher(new MockHttpFetcher("", 0, nullptr));
   fetcher->FailTransfer(503);  // Sets the HTTP response code.
-  DownloadAction action(prefs_, NULL, fetcher.release());
+  DownloadAction action(prefs_, nullptr, fetcher.release());
   EXPECT_CALL(*prefs_, GetInt64(kPrefsDeltaUpdateFailures, _)).Times(0);
-  attempter_.ActionCompleted(NULL, &action, ErrorCode::kSuccess);
+  attempter_.ActionCompleted(nullptr, &action, ErrorCode::kSuccess);
   EXPECT_EQ(503, attempter_.http_response_code());
   EXPECT_EQ(UPDATE_STATUS_FINALIZING, attempter_.status());
-  ASSERT_TRUE(attempter_.error_event_.get() == NULL);
+  ASSERT_EQ(nullptr, attempter_.error_event_.get());
 }
 
 TEST_F(UpdateAttempterTest, ActionCompletedErrorTest) {
@@ -186,14 +186,14 @@
   attempter_.status_ = UPDATE_STATUS_DOWNLOADING;
   EXPECT_CALL(*prefs_, GetInt64(kPrefsDeltaUpdateFailures, _))
       .WillOnce(Return(false));
-  attempter_.ActionCompleted(NULL, &action, ErrorCode::kError);
-  ASSERT_TRUE(attempter_.error_event_.get() != NULL);
+  attempter_.ActionCompleted(nullptr, &action, ErrorCode::kError);
+  ASSERT_NE(nullptr, attempter_.error_event_.get());
 }
 
 TEST_F(UpdateAttempterTest, ActionCompletedOmahaRequestTest) {
-  scoped_ptr<MockHttpFetcher> fetcher(new MockHttpFetcher("", 0, NULL));
+  scoped_ptr<MockHttpFetcher> fetcher(new MockHttpFetcher("", 0, nullptr));
   fetcher->FailTransfer(500);  // Sets the HTTP response code.
-  OmahaRequestAction action(&fake_system_state_, NULL,
+  OmahaRequestAction action(&fake_system_state_, nullptr,
                             fetcher.release(), false);
   ObjectCollectorAction<OmahaResponse> collector_action;
   BondActions(&action, &collector_action);
@@ -203,18 +203,18 @@
   UpdateCheckScheduler scheduler(&attempter_, &fake_system_state_);
   attempter_.set_update_check_scheduler(&scheduler);
   EXPECT_CALL(*prefs_, GetInt64(kPrefsDeltaUpdateFailures, _)).Times(0);
-  attempter_.ActionCompleted(NULL, &action, ErrorCode::kSuccess);
+  attempter_.ActionCompleted(nullptr, &action, ErrorCode::kSuccess);
   EXPECT_EQ(500, attempter_.http_response_code());
   EXPECT_EQ(UPDATE_STATUS_IDLE, attempter_.status());
   EXPECT_EQ(234, scheduler.poll_interval());
-  ASSERT_TRUE(attempter_.error_event_.get() == NULL);
+  ASSERT_TRUE(attempter_.error_event_.get() == nullptr);
 }
 
 TEST_F(UpdateAttempterTest, RunAsRootConstructWithUpdatedMarkerTest) {
   string test_update_completed_marker;
   CHECK(utils::MakeTempFile(
           "update_attempter_unittest-update_completed_marker-XXXXXX",
-          &test_update_completed_marker, NULL));
+          &test_update_completed_marker, nullptr));
   ScopedPathUnlinker completed_marker_unlinker(test_update_completed_marker);
   const base::FilePath marker(test_update_completed_marker);
   EXPECT_EQ(0, base::WriteFile(marker, "", 0));
@@ -227,11 +227,11 @@
   extern ErrorCode GetErrorCodeForAction(AbstractAction* action,
                                               ErrorCode code);
   EXPECT_EQ(ErrorCode::kSuccess,
-            GetErrorCodeForAction(NULL, ErrorCode::kSuccess));
+            GetErrorCodeForAction(nullptr, ErrorCode::kSuccess));
 
   FakeSystemState fake_system_state;
-  OmahaRequestAction omaha_request_action(&fake_system_state, NULL,
-                                          NULL, false);
+  OmahaRequestAction omaha_request_action(&fake_system_state, nullptr,
+                                          nullptr, false);
   EXPECT_EQ(ErrorCode::kOmahaRequestError,
             GetErrorCodeForAction(&omaha_request_action, ErrorCode::kError));
   OmahaResponseHandlerAction omaha_response_handler_action(&fake_system_state_);
@@ -465,7 +465,7 @@
             attempter_.actions_[1].get());
   DownloadAction* download_action =
       dynamic_cast<DownloadAction*>(attempter_.actions_[5].get());
-  ASSERT_TRUE(download_action != NULL);
+  ASSERT_NE(nullptr, download_action);
   EXPECT_EQ(&attempter_, download_action->delegate());
   EXPECT_EQ(UPDATE_STATUS_CHECKING_FOR_UPDATE, attempter_.status());
   g_main_loop_quit(loop_);
@@ -549,7 +549,7 @@
   g_idle_add(&StaticUpdateTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 TEST_F(UpdateAttempterTest, RollbackTest) {
@@ -557,7 +557,7 @@
   g_idle_add(&StaticRollbackTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 TEST_F(UpdateAttempterTest, InvalidSlotRollbackTest) {
@@ -565,7 +565,7 @@
   g_idle_add(&StaticInvalidSlotRollbackTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 TEST_F(UpdateAttempterTest, EnterpriseRollbackTest) {
@@ -573,7 +573,7 @@
   g_idle_add(&StaticEnterpriseRollbackTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 void UpdateAttempterTest::PingOmahaTestStart() {
@@ -595,7 +595,7 @@
   g_idle_add(&StaticPingOmahaTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
   EXPECT_EQ(UPDATE_STATUS_UPDATED_NEED_REBOOT, attempter_.status());
   EXPECT_EQ(true, scheduler.scheduled_);
 }
@@ -604,7 +604,7 @@
   ActionMock action;
   const ErrorCode kCode = ErrorCode::kDownloadTransferError;
   attempter_.CreatePendingErrorEvent(&action, kCode);
-  ASSERT_TRUE(attempter_.error_event_.get() != NULL);
+  ASSERT_NE(nullptr, attempter_.error_event_.get());
   EXPECT_EQ(OmahaEvent::kTypeUpdateComplete, attempter_.error_event_->type);
   EXPECT_EQ(OmahaEvent::kResultError, attempter_.error_event_->result);
   EXPECT_EQ(
@@ -621,7 +621,7 @@
   ActionMock action;
   const ErrorCode kCode = ErrorCode::kInstallDeviceOpenError;
   attempter_.CreatePendingErrorEvent(&action, kCode);
-  ASSERT_TRUE(attempter_.error_event_.get() != NULL);
+  ASSERT_NE(nullptr, attempter_.error_event_.get());
   EXPECT_EQ(OmahaEvent::kTypeUpdateComplete, attempter_.error_event_->type);
   EXPECT_EQ(OmahaEvent::kResultError, attempter_.error_event_->result);
   EXPECT_EQ(
@@ -637,7 +637,7 @@
   g_idle_add(&StaticReadChannelFromPolicyTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 void UpdateAttempterTest::ReadChannelFromPolicyTestStart() {
@@ -672,7 +672,7 @@
   g_idle_add(&StaticReadUpdateDisabledFromPolicyTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 void UpdateAttempterTest::ReadUpdateDisabledFromPolicyTestStart() {
@@ -726,7 +726,7 @@
   g_idle_add(&StaticP2PNotEnabled, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 gboolean UpdateAttempterTest::StaticP2PNotEnabled(gpointer data) {
   UpdateAttempterTest* ua_test = reinterpret_cast<UpdateAttempterTest*>(data);
@@ -751,7 +751,7 @@
   g_idle_add(&StaticP2PEnabledStartingFails, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 gboolean UpdateAttempterTest::StaticP2PEnabledStartingFails(
     gpointer data) {
@@ -779,7 +779,7 @@
   g_idle_add(&StaticP2PEnabledHousekeepingFails, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 gboolean UpdateAttempterTest::StaticP2PEnabledHousekeepingFails(
     gpointer data) {
@@ -807,7 +807,7 @@
   g_idle_add(&StaticP2PEnabled, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 gboolean UpdateAttempterTest::StaticP2PEnabled(gpointer data) {
   UpdateAttempterTest* ua_test = reinterpret_cast<UpdateAttempterTest*>(data);
@@ -834,7 +834,7 @@
   g_idle_add(&StaticP2PEnabledInteractive, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 gboolean UpdateAttempterTest::StaticP2PEnabledInteractive(gpointer data) {
   UpdateAttempterTest* ua_test = reinterpret_cast<UpdateAttempterTest*>(data);
@@ -862,7 +862,7 @@
   g_idle_add(&StaticReadTargetVersionPrefixFromPolicyTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 void UpdateAttempterTest::ReadTargetVersionPrefixFromPolicyTestStart() {
@@ -895,7 +895,7 @@
   g_idle_add(&StaticReadScatterFactorFromPolicyTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 // Tests that the scatter_factor_in_seconds value is properly fetched
@@ -925,7 +925,7 @@
   g_idle_add(&StaticDecrementUpdateCheckCountTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 void UpdateAttempterTest::DecrementUpdateCheckCountTestStart() {
@@ -988,7 +988,7 @@
   g_idle_add(&StaticNoScatteringDoneDuringManualUpdateTestStart, this);
   g_main_loop_run(loop_);
   g_main_loop_unref(loop_);
-  loop_ = NULL;
+  loop_ = nullptr;
 }
 
 void UpdateAttempterTest::NoScatteringDoneDuringManualUpdateTestStart() {
diff --git a/update_check_scheduler.cc b/update_check_scheduler.cc
index 8eff465..5358416 100644
--- a/update_check_scheduler.cc
+++ b/update_check_scheduler.cc
@@ -32,7 +32,7 @@
 
 void UpdateCheckScheduler::Run() {
   enabled_ = false;
-  update_attempter_->set_update_check_scheduler(NULL);
+  update_attempter_->set_update_check_scheduler(nullptr);
 
   if (!system_state_->hardware()->IsOfficialBuild()) {
     LOG(WARNING) << "Non-official build: periodic update checks disabled.";
diff --git a/update_check_scheduler_unittest.cc b/update_check_scheduler_unittest.cc
index cd79a23..dda3b40 100644
--- a/update_check_scheduler_unittest.cc
+++ b/update_check_scheduler_unittest.cc
@@ -53,7 +53,7 @@
  protected:
   virtual void SetUp() {
     test_ = this;
-    loop_ = NULL;
+    loop_ = nullptr;
     EXPECT_EQ(&attempter_, scheduler_.update_attempter_);
     EXPECT_FALSE(scheduler_.enabled_);
     EXPECT_FALSE(scheduler_.scheduled_);
@@ -65,8 +65,8 @@
   }
 
   virtual void TearDown() {
-    test_ = NULL;
-    loop_ = NULL;
+    test_ = nullptr;
+    loop_ = nullptr;
   }
 
   static gboolean SourceCallback(gpointer data) {
@@ -85,7 +85,7 @@
   static UpdateCheckSchedulerTest* test_;
 };
 
-UpdateCheckSchedulerTest* UpdateCheckSchedulerTest::test_ = NULL;
+UpdateCheckSchedulerTest* UpdateCheckSchedulerTest::test_ = nullptr;
 
 TEST_F(UpdateCheckSchedulerTest, CanScheduleTest) {
   EXPECT_FALSE(scheduler_.CanSchedule());
@@ -169,7 +169,7 @@
   fake_system_state_.fake_hardware()->SetIsBootDeviceRemovable(true);
   scheduler_.Run();
   EXPECT_FALSE(scheduler_.enabled_);
-  EXPECT_EQ(NULL, attempter_.update_check_scheduler());
+  EXPECT_EQ(nullptr, attempter_.update_check_scheduler());
 }
 
 TEST_F(UpdateCheckSchedulerTest, RunNonOfficialBuildTest) {
@@ -177,7 +177,7 @@
   fake_system_state_.fake_hardware()->SetIsOfficialBuild(false);
   scheduler_.Run();
   EXPECT_FALSE(scheduler_.enabled_);
-  EXPECT_EQ(NULL, attempter_.update_check_scheduler());
+  EXPECT_EQ(nullptr, attempter_.update_check_scheduler());
 }
 
 TEST_F(UpdateCheckSchedulerTest, RunTest) {
@@ -268,7 +268,7 @@
 
 TEST_F(UpdateCheckSchedulerTest, StaticCheckOOBECompleteTest) {
   scheduler_.scheduled_ = true;
-  EXPECT_TRUE(scheduler_.fake_system_state_ != NULL);
+  EXPECT_NE(nullptr, scheduler_.fake_system_state_);
   scheduler_.fake_system_state_->fake_hardware()->SetIsOOBEComplete(
       Time::UnixEpoch());
   EXPECT_CALL(attempter_, Update("", "", false, false))
diff --git a/update_engine_client.cc b/update_engine_client.cc
index eb092b5..37d52d6 100644
--- a/update_engine_client.cc
+++ b/update_engine_client.cc
@@ -71,13 +71,13 @@
 
 bool GetProxy(DBusGProxy** out_proxy) {
   DBusGConnection* bus;
-  DBusGProxy* proxy = NULL;
-  GError* error = NULL;
+  DBusGProxy* proxy = nullptr;
+  GError* error = nullptr;
   const int kTries = 4;
   const int kRetrySeconds = 10;
 
   bus = dbus_g_bus_get(DBUS_BUS_SYSTEM, &error);
-  if (bus == NULL) {
+  if (bus == nullptr) {
     LOG(ERROR) << "Failed to get bus: " << GetAndFreeGError(&error);
     exit(1);
   }
@@ -96,7 +96,7 @@
                             << kUpdateEngineServiceName << ": "
                             << GetAndFreeGError(&error);
   }
-  if (proxy == NULL) {
+  if (proxy == nullptr) {
     LOG(ERROR) << "Giving up -- unable to get dbus proxy for "
                << kUpdateEngineServiceName;
     exit(1);
@@ -122,7 +122,7 @@
 
 bool ResetStatus() {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -131,18 +131,18 @@
 }
 
 
-// If |op| is non-NULL, sets it to the current operation string or an
+// If |op| is non-null, sets it to the current operation string or an
 // empty string if unable to obtain the current status.
 bool GetStatus(string* op) {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
   gint64 last_checked_time = 0;
   gdouble progress = 0.0;
-  char* current_op = NULL;
-  char* new_version = NULL;
+  char* current_op = nullptr;
+  char* new_version = nullptr;
   gint64 new_size = 0;
 
   gboolean rc = update_engine_client_get_status(proxy,
@@ -194,19 +194,19 @@
                           G_TYPE_STRING,
                           G_TYPE_INT64,
                           G_TYPE_INVALID);
-  GMainLoop* loop = g_main_loop_new(NULL, TRUE);
+  GMainLoop* loop = g_main_loop_new(nullptr, TRUE);
   dbus_g_proxy_connect_signal(proxy,
                               kStatusUpdate,
                               G_CALLBACK(StatusUpdateSignalHandler),
-                              NULL,
-                              NULL);
+                              nullptr,
+                              nullptr);
   g_main_loop_run(loop);
   g_main_loop_unref(loop);
 }
 
 bool Rollback(bool rollback) {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -220,7 +220,7 @@
 
 std::string GetRollbackPartition() {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -254,7 +254,7 @@
 
 bool CheckForUpdates(const string& app_version, const string& omaha_url) {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -273,7 +273,7 @@
 
 bool RebootIfNeeded() {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -288,7 +288,7 @@
 
 void SetTargetChannel(const string& target_channel, bool allow_powerwash) {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -303,11 +303,11 @@
 
 string GetChannel(bool get_current_channel) {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
-  char* channel = NULL;
+  char* channel = nullptr;
   gboolean rc = update_engine_client_get_channel(proxy,
                                                  get_current_channel,
                                                  &channel,
@@ -321,7 +321,7 @@
 
 void SetUpdateOverCellularPermission(gboolean allowed) {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -335,7 +335,7 @@
 
 bool GetUpdateOverCellularPermission() {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -351,7 +351,7 @@
 
 void SetP2PUpdatePermission(gboolean enabled) {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -365,7 +365,7 @@
 
 bool GetP2PUpdatePermission() {
   DBusGProxy* proxy;
-  GError* error = NULL;
+  GError* error = nullptr;
 
   CHECK(GetProxy(&proxy));
 
@@ -396,8 +396,8 @@
 // a signal watch, actively poll the daemon just in case it stops
 // sending notifications.
 void CompleteUpdate() {
-  GMainLoop* loop = g_main_loop_new(NULL, TRUE);
-  g_timeout_add_seconds(5, CompleteUpdateSource, NULL);
+  GMainLoop* loop = g_main_loop_new(nullptr, TRUE);
+  g_timeout_add_seconds(5, CompleteUpdateSource, nullptr);
   g_main_loop_run(loop);
   g_main_loop_unref(loop);
 }
@@ -663,7 +663,7 @@
 
   if (FLAGS_status) {
     LOG(INFO) << "Querying Update Engine status...";
-    if (!GetStatus(NULL)) {
+    if (!GetStatus(nullptr)) {
       LOG(ERROR) << "GetStatus failed.";
       return 1;
     }
diff --git a/update_manager/boxed_value.h b/update_manager/boxed_value.h
index 4b8517f..6b547b6 100644
--- a/update_manager/boxed_value.h
+++ b/update_manager/boxed_value.h
@@ -43,7 +43,7 @@
   // Creates an empty BoxedValue. Since the pointer can't be assigned from other
   // BoxedValues or pointers, this is only useful in places where a default
   // constructor is required, such as std::map::operator[].
-  BoxedValue() : value_(NULL), deleter_(NULL), printer_(NULL) {}
+  BoxedValue() : value_(nullptr), deleter_(nullptr), printer_(nullptr) {}
 
   // Creates a BoxedValue for the passed pointer |value|. The BoxedValue keeps
   // the ownership of this pointer and can't be released.
@@ -60,9 +60,9 @@
   BoxedValue(BoxedValue&& other)  // NOLINT(build/c++11)
       : value_(other.value_), deleter_(other.deleter_),
         printer_(other.printer_) {
-    other.value_ = NULL;
-    other.deleter_ = NULL;
-    other.printer_ = NULL;
+    other.value_ = nullptr;
+    other.deleter_ = nullptr;
+    other.printer_ = nullptr;
   }
 
   // Deletes the |value| passed on construction using the delete for the passed
diff --git a/update_manager/boxed_value_unittest.cc b/update_manager/boxed_value_unittest.cc
index 1b03cdd..dff6738 100644
--- a/update_manager/boxed_value_unittest.cc
+++ b/update_manager/boxed_value_unittest.cc
@@ -89,8 +89,8 @@
 
   auto it = m.find(42);
   ASSERT_NE(it, m.end());
-  UMTEST_EXPECT_NOT_NULL(it->second.value());
-  UMTEST_EXPECT_NULL(m[33].value());
+  EXPECT_NE(nullptr, it->second.value());
+  EXPECT_EQ(nullptr, m[33].value());
 }
 
 TEST(UmBoxedValueTest, StringToString) {
diff --git a/update_manager/evaluation_context.cc b/update_manager/evaluation_context.cc
index 5bee226..e334560 100644
--- a/update_manager/evaluation_context.cc
+++ b/update_manager/evaluation_context.cc
@@ -146,7 +146,7 @@
 
 bool EvaluationContext::RunOnValueChangeOrTimeout(Closure callback) {
   // Check that the method was not called more than once.
-  if (callback_.get() != nullptr) {
+  if (callback_.get()) {
     LOG(ERROR) << "RunOnValueChangeOrTimeout called more than once.";
     return false;
   }
diff --git a/update_manager/evaluation_context.h b/update_manager/evaluation_context.h
index e743669..a6d8f70 100644
--- a/update_manager/evaluation_context.h
+++ b/update_manager/evaluation_context.h
@@ -70,7 +70,7 @@
   // returned object is valid during the life of the evaluation, even if the
   // passed Variable changes it.
   //
-  // In case of error, a NULL value is returned.
+  // In case of error, a null value is returned.
   template<typename T>
   const T* GetValue(Variable<T>* var);
 
diff --git a/update_manager/evaluation_context_unittest.cc b/update_manager/evaluation_context_unittest.cc
index e193718..e59b160 100644
--- a/update_manager/evaluation_context_unittest.cc
+++ b/update_manager/evaluation_context_unittest.cc
@@ -84,9 +84,9 @@
     if (eval_ctx_) {
       base::WeakPtr<EvaluationContext> eval_ctx_weak_alias =
           eval_ctx_->weak_ptr_factory_.GetWeakPtr();
-      UMTEST_ASSERT_NOT_NULL(eval_ctx_weak_alias.get());
+      ASSERT_NE(nullptr, eval_ctx_weak_alias.get());
       eval_ctx_ = nullptr;
-      UMTEST_EXPECT_NULL(eval_ctx_weak_alias.get())
+      EXPECT_EQ(nullptr, eval_ctx_weak_alias.get())
           << "The evaluation context was not destroyed! This is likely a bug "
              "in how the test was written, look for leaking handles to the EC, "
              "possibly through closure objects.";
@@ -120,13 +120,12 @@
 };
 
 TEST_F(UmEvaluationContextTest, GetValueFails) {
-  // FakeVariable is initialized as returning NULL.
-  UMTEST_EXPECT_NULL(eval_ctx_->GetValue(&fake_int_var_));
+  // FakeVariable is initialized as returning null.
+  EXPECT_EQ(nullptr, eval_ctx_->GetValue(&fake_int_var_));
 }
 
 TEST_F(UmEvaluationContextTest, GetValueFailsWithInvalidVar) {
-  UMTEST_EXPECT_NULL(eval_ctx_->GetValue(
-      reinterpret_cast<Variable<int>*>(NULL)));
+  EXPECT_EQ(nullptr, eval_ctx_->GetValue(static_cast<Variable<int>*>(nullptr)));
 }
 
 TEST_F(UmEvaluationContextTest, GetValueReturns) {
@@ -134,7 +133,7 @@
 
   fake_int_var_.reset(new int(42));
   p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
-  UMTEST_ASSERT_NOT_NULL(p_fake_int);
+  ASSERT_NE(nullptr, p_fake_int);
   EXPECT_EQ(42, *p_fake_int);
 }
 
@@ -149,19 +148,19 @@
   fake_int_var_.reset(new int(5));
 
   p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
-  UMTEST_ASSERT_NOT_NULL(p_fake_int);
+  ASSERT_NE(nullptr, p_fake_int);
   EXPECT_EQ(42, *p_fake_int);
 }
 
 TEST_F(UmEvaluationContextTest, GetValueCachesNull) {
   const int* p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
-  UMTEST_EXPECT_NULL(p_fake_int);
+  EXPECT_EQ(nullptr, p_fake_int);
 
   fake_int_var_.reset(new int(42));
   // A second attempt to read the variable should not work because this
-  // EvaluationContext already got a NULL value.
+  // EvaluationContext already got a null value.
   p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
-  UMTEST_EXPECT_NULL(p_fake_int);
+  EXPECT_EQ(nullptr, p_fake_int);
 }
 
 TEST_F(UmEvaluationContextTest, GetValueMixedTypes) {
@@ -175,10 +174,10 @@
   p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
   p_fake_string = eval_ctx_->GetValue(&fake_poll_var_);
 
-  UMTEST_ASSERT_NOT_NULL(p_fake_int);
+  ASSERT_NE(nullptr, p_fake_int);
   EXPECT_EQ(42, *p_fake_int);
 
-  UMTEST_ASSERT_NOT_NULL(p_fake_string);
+  ASSERT_NE(nullptr, p_fake_string);
   EXPECT_EQ("Hello world!", *p_fake_string);
 }
 
@@ -328,7 +327,7 @@
   // setup.
   EXPECT_CALL(mock_var_async_, GetValue(default_timeout_, _))
       .WillOnce(Return(nullptr));
-  UMTEST_EXPECT_NULL(eval_ctx_->GetValue(&mock_var_async_));
+  EXPECT_EQ(nullptr, eval_ctx_->GetValue(&mock_var_async_));
 }
 
 TEST_F(UmEvaluationContextTest, TimeoutUpdatesWithMonotonicTime) {
@@ -339,7 +338,7 @@
 
   EXPECT_CALL(mock_var_async_, GetValue(timeout, _))
       .WillOnce(Return(nullptr));
-  UMTEST_EXPECT_NULL(eval_ctx_->GetValue(&mock_var_async_));
+  EXPECT_EQ(nullptr, eval_ctx_->GetValue(&mock_var_async_));
 }
 
 TEST_F(UmEvaluationContextTest, ResetEvaluationResetsTimesWallclock) {
diff --git a/update_manager/fake_variable.h b/update_manager/fake_variable.h
index 6024b75..2dae3db 100644
--- a/update_manager/fake_variable.h
+++ b/update_manager/fake_variable.h
@@ -26,7 +26,8 @@
 
   // Sets the next value of this variable to the passed |p_value| pointer. Once
   // returned by GetValue(), the pointer is released and has to be set again.
-  // A value of NULL means that the GetValue() call will fail and return NULL.
+  // A value of null means that the GetValue() call will fail and return
+  // null.
   void reset(const T* p_value) {
     ptr_.reset(p_value);
   }
@@ -40,11 +41,11 @@
   // Variable<T> overrides.
   // Returns the pointer set with reset(). The ownership of the object is passed
   // to the caller and the pointer is release from the FakeVariable. A second
-  // call to GetValue() without reset() will return NULL and set the error
+  // call to GetValue() without reset() will return null and set the error
   // message.
   virtual const T* GetValue(base::TimeDelta /* timeout */,
                             std::string* errmsg) {
-    if (ptr_ == NULL && errmsg != NULL)
+    if (ptr_ == nullptr && errmsg != nullptr)
       *errmsg = this->GetName() + " is an empty FakeVariable";
     // Passes the pointer ownership to the caller.
     return ptr_.release();
diff --git a/update_manager/generic_variables_unittest.cc b/update_manager/generic_variables_unittest.cc
index bbf3996..634acce 100644
--- a/update_manager/generic_variables_unittest.cc
+++ b/update_manager/generic_variables_unittest.cc
@@ -26,8 +26,8 @@
 
   // Generate and validate a copy.
   scoped_ptr<const int> copy_1(var.GetValue(
-          UmTestUtils::DefaultTimeout(), NULL));
-  UMTEST_ASSERT_NOT_NULL(copy_1.get());
+          UmTestUtils::DefaultTimeout(), nullptr));
+  ASSERT_NE(nullptr, copy_1.get());
   EXPECT_EQ(5, *copy_1);
 
   // Assign a different value to the source variable.
@@ -76,8 +76,8 @@
 
   PollCopyVariable<CopyConstructorTestClass> var("var", source);
   scoped_ptr<const CopyConstructorTestClass> copy(
-      var.GetValue(UmTestUtils::DefaultTimeout(), NULL));
-  UMTEST_ASSERT_NOT_NULL(copy.get());
+      var.GetValue(UmTestUtils::DefaultTimeout(), nullptr));
+  ASSERT_NE(nullptr, copy.get());
   EXPECT_TRUE(copy->copied_);
 }
 
@@ -117,7 +117,7 @@
   scoped_ptr<const CopyConstructorTestClass> copy(
       var.GetValue(UmTestUtils::DefaultTimeout(), nullptr));
   EXPECT_EQ(6, test_obj.val_);  // Check that the function was called.
-  UMTEST_ASSERT_NOT_NULL(copy.get());
+  ASSERT_NE(nullptr, copy.get());
   EXPECT_TRUE(copy->copied_);
   EXPECT_EQ(12, copy->val_);  // Check that copying occurred once.
 }
diff --git a/update_manager/real_config_provider_unittest.cc b/update_manager/real_config_provider_unittest.cc
index fc20e36..93e657d 100644
--- a/update_manager/real_config_provider_unittest.cc
+++ b/update_manager/real_config_provider_unittest.cc
@@ -51,7 +51,7 @@
 
 TEST_F(UmRealConfigProviderTest, InitTest) {
   EXPECT_TRUE(provider_->Init());
-  UMTEST_EXPECT_NOT_NULL(provider_->var_is_oobe_enabled());
+  EXPECT_NE(nullptr, provider_->var_is_oobe_enabled());
 }
 
 TEST_F(UmRealConfigProviderTest, NoFileFoundReturnsDefault) {
diff --git a/update_manager/real_random_provider.cc b/update_manager/real_random_provider.cc
index abbeed7..ea10de6 100644
--- a/update_manager/real_random_provider.cc
+++ b/update_manager/real_random_provider.cc
@@ -51,7 +51,7 @@
           *errmsg = base::StringPrintf(
               "Error reading from the random device: %s", kRandomDevice);
         }
-        return NULL;
+        return nullptr;
       }
       buf_rd += rd;
     }
diff --git a/update_manager/real_random_provider_unittest.cc b/update_manager/real_random_provider_unittest.cc
index 55e17fa..b7e48f2 100644
--- a/update_manager/real_random_provider_unittest.cc
+++ b/update_manager/real_random_provider_unittest.cc
@@ -17,7 +17,7 @@
   virtual void SetUp() {
     // The provider initializes correctly.
     provider_.reset(new RealRandomProvider());
-    UMTEST_ASSERT_NOT_NULL(provider_.get());
+    ASSERT_NE(nullptr, provider_.get());
     ASSERT_TRUE(provider_->Init());
 
     provider_->var_seed();
@@ -28,14 +28,14 @@
 
 TEST_F(UmRealRandomProviderTest, InitFinalize) {
   // The provider initializes all variables with valid objects.
-  UMTEST_EXPECT_NOT_NULL(provider_->var_seed());
+  EXPECT_NE(nullptr, provider_->var_seed());
 }
 
 TEST_F(UmRealRandomProviderTest, GetRandomValues) {
   // Should not return the same random seed repeatedly.
   scoped_ptr<const uint64_t> value(
       provider_->var_seed()->GetValue(UmTestUtils::DefaultTimeout(), nullptr));
-  UMTEST_ASSERT_NOT_NULL(value.get());
+  ASSERT_NE(nullptr, value.get());
 
   // Test that at least the returned values are different. This test fails,
   // by design, once every 2^320 runs.
@@ -44,7 +44,7 @@
     scoped_ptr<const uint64_t> other_value(
         provider_->var_seed()->GetValue(UmTestUtils::DefaultTimeout(),
                                         nullptr));
-    UMTEST_ASSERT_NOT_NULL(other_value.get());
+    ASSERT_NE(nullptr, other_value.get());
     is_same_value = is_same_value && *other_value == *value;
   }
   EXPECT_FALSE(is_same_value);
diff --git a/update_manager/real_shill_provider.cc b/update_manager/real_shill_provider.cc
index dd8261c..609fd01 100644
--- a/update_manager/real_shill_provider.cc
+++ b/update_manager/real_shill_provider.cc
@@ -20,7 +20,7 @@
 // the corresponding GValue, if found.
 const char* GetStrProperty(GHashTable* hash_table, const char* key) {
   auto gval = reinterpret_cast<GValue*>(g_hash_table_lookup(hash_table, key));
-  return (gval ? g_value_get_string(gval) : NULL);
+  return (gval ? g_value_get_string(gval) : nullptr);
 }
 
 };  // namespace
@@ -65,7 +65,7 @@
 
 bool RealShillProvider::Init() {
   // Obtain a DBus connection.
-  GError* error = NULL;
+  GError* error = nullptr;
   connection_ = dbus_->BusGet(DBUS_BUS_SYSTEM, &error);
   if (!connection_) {
     LOG(ERROR) << "Failed to initialize DBus connection: "
@@ -82,12 +82,12 @@
                           G_TYPE_STRING, G_TYPE_VALUE);
   dbus_->ProxyConnectSignal(manager_proxy_, shill::kMonitorPropertyChanged,
                             G_CALLBACK(HandlePropertyChangedStatic),
-                            this, NULL);
+                            this, nullptr);
 
   // Attempt to read initial connection status. Even if this fails because shill
   // is not responding (e.g. it is down) we'll be notified via "PropertyChanged"
   // signal as soon as it comes up, so this is not a critical step.
-  GHashTable* hash_table = NULL;
+  GHashTable* hash_table = nullptr;
   if (GetProperties(manager_proxy_, &hash_table)) {
     GValue* value = reinterpret_cast<GValue*>(
         g_hash_table_lookup(hash_table, shill::kDefaultServiceProperty));
@@ -106,7 +106,7 @@
 
 bool RealShillProvider::GetProperties(DBusGProxy* proxy,
                                       GHashTable** result_p) {
-  GError* error = NULL;
+  GError* error = nullptr;
   if (!dbus_->ProxyCall_0_1(proxy, shill::kGetPropertiesFunction, &error,
                             result_p)) {
     LOG(ERROR) << "Calling shill via DBus proxy failed: "
@@ -118,7 +118,7 @@
 
 bool RealShillProvider::ProcessDefaultService(GValue* value) {
   // Decode the string from the boxed value.
-  const char* default_service_path_str = NULL;
+  const char* default_service_path_str = nullptr;
   if (!(value && (default_service_path_str = g_value_get_string(value))))
     return false;
 
@@ -136,7 +136,7 @@
   if (is_connected) {
     DBusGProxy* service_proxy = GetProxy(default_service_path_.c_str(),
                                          shill::kFlimflamServiceInterface);
-    GHashTable* hash_table = NULL;
+    GHashTable* hash_table = nullptr;
     if (GetProperties(service_proxy, &hash_table)) {
       // Get the connection type.
       const char* type_str = GetStrProperty(hash_table, shill::kTypeProperty);
diff --git a/update_manager/real_shill_provider.h b/update_manager/real_shill_provider.h
index 382aa1e..716a7dd 100644
--- a/update_manager/real_shill_provider.h
+++ b/update_manager/real_shill_provider.h
@@ -77,8 +77,8 @@
 
   // The DBus interface (mockable), connection, and a shill manager proxy.
   DBusWrapperInterface* const dbus_;
-  DBusGConnection* connection_ = NULL;
-  DBusGProxy* manager_proxy_ = NULL;
+  DBusGConnection* connection_ = nullptr;
+  DBusGProxy* manager_proxy_ = nullptr;
 
   // A clock abstraction (mockable).
   ClockInterface* const clock_;
diff --git a/update_manager/real_shill_provider_unittest.cc b/update_manager/real_shill_provider_unittest.cc
index 3468517..1cdc2a9 100644
--- a/update_manager/real_shill_provider_unittest.cc
+++ b/update_manager/real_shill_provider_unittest.cc
@@ -82,7 +82,7 @@
       Shutdown();
 
     provider_.reset(new RealShillProvider(&mock_dbus_, &fake_clock_));
-    UMTEST_ASSERT_NOT_NULL(provider_.get());
+    ASSERT_NE(nullptr, provider_.get());
     fake_clock_.SetWallclockTime(InitTime());
 
     // A DBus connection should only be obtained once.
diff --git a/update_manager/real_system_provider_unittest.cc b/update_manager/real_system_provider_unittest.cc
index d744671..f78d339 100644
--- a/update_manager/real_system_provider_unittest.cc
+++ b/update_manager/real_system_provider_unittest.cc
@@ -25,9 +25,9 @@
 };
 
 TEST_F(UmRealSystemProviderTest, InitTest) {
-  UMTEST_EXPECT_NOT_NULL(provider_->var_is_normal_boot_mode());
-  UMTEST_EXPECT_NOT_NULL(provider_->var_is_official_build());
-  UMTEST_EXPECT_NOT_NULL(provider_->var_is_oobe_complete());
+  EXPECT_NE(nullptr, provider_->var_is_normal_boot_mode());
+  EXPECT_NE(nullptr, provider_->var_is_official_build());
+  EXPECT_NE(nullptr, provider_->var_is_oobe_complete());
 }
 
 TEST_F(UmRealSystemProviderTest, IsOOBECompleteTrue) {
diff --git a/update_manager/real_time_provider_unittest.cc b/update_manager/real_time_provider_unittest.cc
index 6b236db..ac47d39 100644
--- a/update_manager/real_time_provider_unittest.cc
+++ b/update_manager/real_time_provider_unittest.cc
@@ -22,7 +22,7 @@
   virtual void SetUp() {
     // The provider initializes correctly.
     provider_.reset(new RealTimeProvider(&fake_clock_));
-    UMTEST_ASSERT_NOT_NULL(provider_.get());
+    ASSERT_NE(nullptr, provider_.get());
     ASSERT_TRUE(provider_->Init());
   }
 
diff --git a/update_manager/real_updater_provider.cc b/update_manager/real_updater_provider.cc
index c525b8f..004b51a 100644
--- a/update_manager/real_updater_provider.cc
+++ b/update_manager/real_updater_provider.cc
@@ -81,7 +81,7 @@
   const Time* GetValue(TimeDelta /* timeout */, string* errmsg) override {
     GetStatusHelper raw(system_state(), errmsg);
     if (!raw.is_success())
-      return NULL;
+      return nullptr;
 
     return new Time(Time::FromTimeT(raw.last_checked_time()));
   }
@@ -100,14 +100,14 @@
   const double* GetValue(TimeDelta /* timeout */, string* errmsg) override {
     GetStatusHelper raw(system_state(), errmsg);
     if (!raw.is_success())
-      return NULL;
+      return nullptr;
 
     if (raw.progress() < 0.0 || raw.progress() > 1.0) {
       if (errmsg) {
         *errmsg = StringPrintf("Invalid progress value received: %f",
                                raw.progress());
       }
-      return NULL;
+      return nullptr;
     }
 
     return new double(raw.progress());
@@ -154,7 +154,7 @@
                                      string* errmsg) {
   GetStatusHelper raw(system_state(), errmsg);
   if (!raw.is_success())
-    return NULL;
+    return nullptr;
 
   for (auto& key_val : curr_op_str_to_stage)
     if (raw.update_status() == key_val.str)
@@ -162,7 +162,7 @@
 
   if (errmsg)
     *errmsg = string("Unknown update status: ") + raw.update_status();
-  return NULL;
+  return nullptr;
 }
 
 // A variable reporting the version number that an update is updating to.
@@ -175,7 +175,7 @@
   const string* GetValue(TimeDelta /* timeout */, string* errmsg) override {
     GetStatusHelper raw(system_state(), errmsg);
     if (!raw.is_success())
-      return NULL;
+      return nullptr;
 
     return new string(raw.new_version());
   }
@@ -193,12 +193,12 @@
   const int64_t* GetValue(TimeDelta /* timeout */, string* errmsg) override {
     GetStatusHelper raw(system_state(), errmsg);
     if (!raw.is_success())
-      return NULL;
+      return nullptr;
 
     if (raw.payload_size() < 0) {
       if (errmsg)
         *errmsg = string("Invalid payload size: %" PRId64, raw.payload_size());
-      return NULL;
+      return nullptr;
     }
 
     return new int64_t(raw.payload_size());
@@ -226,7 +226,7 @@
             &update_boottime)) {
       if (errmsg)
         *errmsg = "Update completed time could not be read";
-      return NULL;
+      return nullptr;
     }
 
     chromeos_update_engine::ClockInterface* clock = system_state()->clock();
@@ -234,7 +234,7 @@
     if (curr_boottime < update_boottime) {
       if (errmsg)
         *errmsg = "Update completed time more recent than current time";
-      return NULL;
+      return nullptr;
     }
     TimeDelta duration_since_update = curr_boottime - update_boottime;
     return new Time(clock->GetWallclockTime() - duration_since_update);
@@ -256,7 +256,7 @@
     if (channel.empty()) {
       if (errmsg)
         *errmsg = "No current channel";
-      return NULL;
+      return nullptr;
     }
     return new string(channel);
   }
@@ -277,7 +277,7 @@
     if (channel.empty()) {
       if (errmsg)
         *errmsg = "No new channel";
-      return NULL;
+      return nullptr;
     }
     return new string(channel);
   }
@@ -300,7 +300,7 @@
     if (prefs && prefs->Exists(key_) && !prefs->GetBoolean(key_, &result)) {
       if (errmsg)
         *errmsg = string("Could not read boolean pref ") + key_;
-      return NULL;
+      return nullptr;
     }
     return new bool(result);
   }
diff --git a/update_manager/real_updater_provider_unittest.cc b/update_manager/real_updater_provider_unittest.cc
index 6e34fe4..6d614da 100644
--- a/update_manager/real_updater_provider_unittest.cc
+++ b/update_manager/real_updater_provider_unittest.cc
@@ -65,7 +65,7 @@
   virtual void SetUp() {
     fake_clock_ = fake_sys_state_.fake_clock();
     provider_.reset(new RealUpdaterProvider(&fake_sys_state_));
-    UMTEST_ASSERT_NOT_NULL(provider_.get());
+    ASSERT_NE(nullptr, provider_.get());
     // Check that provider initializes correctly.
     ASSERT_TRUE(provider_->Init());
   }
diff --git a/update_manager/state_factory.cc b/update_manager/state_factory.cc
index 6aa1761..e9b576a 100644
--- a/update_manager/state_factory.cc
+++ b/update_manager/state_factory.cc
@@ -44,7 +44,7 @@
         time_provider->Init() &&
         updater_provider->Init())) {
     LOG(ERROR) << "Error initializing providers";
-    return NULL;
+    return nullptr;
   }
 
   return new RealState(config_provider.release(),
diff --git a/update_manager/umtest_utils.h b/update_manager/umtest_utils.h
index 3c9036e..4e2de8e 100644
--- a/update_manager/umtest_utils.h
+++ b/update_manager/umtest_utils.h
@@ -14,22 +14,6 @@
 #include "update_engine/update_manager/policy.h"
 #include "update_engine/update_manager/variable.h"
 
-// Convenience macros for checking null-ness of pointers.
-//
-// Purportedly, gtest should support pointer comparison when the first argument
-// is a pointer (e.g. NULL). It is therefore appropriate to use
-// {ASSERT,EXPECT}_{EQ,NE} for our purposes. However, gtest fails to realize
-// that NULL is a pointer when used with the _NE variants, unless we explicitly
-// cast it to a pointer type, and so we inject this casting.
-//
-// Note that checking nullness of the content of a scoped_ptr requires getting
-// the inner pointer value via get().
-#define UMTEST_ASSERT_NULL(p) ASSERT_EQ(NULL, p)
-#define UMTEST_ASSERT_NOT_NULL(p) ASSERT_NE(reinterpret_cast<void*>(NULL), p)
-#define UMTEST_EXPECT_NULL(p) EXPECT_EQ(NULL, p)
-#define UMTEST_EXPECT_NOT_NULL(p) EXPECT_NE(reinterpret_cast<void*>(NULL), p)
-
-
 namespace chromeos_update_manager {
 
 // A help class with common functionality for use in Update Manager testing.
@@ -43,18 +27,18 @@
   // Calls GetValue on |variable| and expects its result to be |expected|.
   template<typename T>
   static void ExpectVariableHasValue(const T& expected, Variable<T>* variable) {
-    UMTEST_ASSERT_NOT_NULL(variable);
+    ASSERT_NE(nullptr, variable);
     scoped_ptr<const T> value(variable->GetValue(DefaultTimeout(), nullptr));
-    UMTEST_ASSERT_NOT_NULL(value.get()) << "Variable: " << variable->GetName();
+    ASSERT_NE(nullptr, value.get()) << "Variable: " << variable->GetName();
     EXPECT_EQ(expected, *value) << "Variable: " << variable->GetName();
   }
 
   // Calls GetValue on |variable| and expects its result to be null.
   template<typename T>
   static void ExpectVariableNotSet(Variable<T>* variable) {
-    UMTEST_ASSERT_NOT_NULL(variable);
+    ASSERT_NE(nullptr, variable);
     scoped_ptr<const T> value(variable->GetValue(DefaultTimeout(), nullptr));
-    UMTEST_EXPECT_NULL(value.get()) << "Variable: " << variable->GetName();
+    EXPECT_EQ(nullptr, value.get()) << "Variable: " << variable->GetName();
   }
 
  private:
diff --git a/update_manager/update_manager.h b/update_manager/update_manager.h
index 8cfd8f4..3355b60 100644
--- a/update_manager/update_manager.h
+++ b/update_manager/update_manager.h
@@ -44,8 +44,8 @@
   // PolicyRequest() evaluates the given policy with the provided arguments and
   // returns the result. The |policy_method| is the pointer-to-method of the
   // Policy class for the policy request to call. The UpdateManager will call
-  // this method on the right policy. The pointer |result| must not be NULL and
-  // the remaining |args| depend on the arguments required by the passed
+  // this method on the right policy. The pointer |result| must not be null
+  // and the remaining |args| depend on the arguments required by the passed
   // |policy_method|.
   //
   // When the policy request succeeds, the |result| is set and the method
diff --git a/update_manager/variable.h b/update_manager/variable.h
index e90d07e..ad2eefa 100644
--- a/update_manager/variable.h
+++ b/update_manager/variable.h
@@ -188,9 +188,9 @@
   // should delete it.
   //
   // In case of and error getting the current value or the |timeout| timeout is
-  // exceeded, a NULL value is returned and the |errmsg| is set.
+  // exceeded, a null value is returned and the |errmsg| is set.
   //
-  // The caller can pass a NULL value for |errmsg|, in which case the error
+  // The caller can pass a null value for |errmsg|, in which case the error
   // message won't be set.
   virtual const T* GetValue(base::TimeDelta timeout, std::string* errmsg) = 0;
 
diff --git a/utils.cc b/utils.cc
index ed57c14..6c527b3 100644
--- a/utils.cc
+++ b/utils.cc
@@ -323,8 +323,8 @@
     if (dir_ && *dir_) {
       int r = closedir(*dir_);
       TEST_AND_RETURN_ERRNO(r == 0);
-      *dir_ = NULL;
-      dir_ = NULL;
+      *dir_ = nullptr;
+      dir_ = nullptr;
     }
   }
  private:
@@ -354,7 +354,7 @@
     struct dirent *dir_entry_p;
     int err = 0;
     while ((err = readdir_r(dir, &dir_entry, &dir_entry_p)) == 0) {
-      if (dir_entry_p == NULL) {
+      if (dir_entry_p == nullptr) {
         // end of stream reached
         break;
       }
@@ -575,7 +575,7 @@
   buf[dirname_template.size()] = '\0';
 
   char* return_code = mkdtemp(&buf[0]);
-  TEST_AND_RETURN_FALSE_ERRNO(return_code != NULL);
+  TEST_AND_RETURN_FALSE_ERRNO(return_code != nullptr);
   *dirname = &buf[0];
   return true;
 }
@@ -595,7 +595,8 @@
 bool MountFilesystem(const string& device,
                      const string& mountpoint,
                      unsigned long mountflags) {  // NOLINT(runtime/int)
-  int rc = mount(device.c_str(), mountpoint.c_str(), "ext3", mountflags, NULL);
+  int rc = mount(device.c_str(), mountpoint.c_str(), "ext3", mountflags,
+                 nullptr);
   if (rc < 0) {
     string msg = ErrnoNumberAsString(errno);
     LOG(ERROR) << "Unable to mount destination device: " << msg << ". "
@@ -792,14 +793,14 @@
     abort();  // never returns
   }
   // We are the parent. Wait for child to terminate.
-  pid_t result = waitpid(pid, NULL, 0);
+  pid_t result = waitpid(pid, nullptr, 0);
   LOG_IF(ERROR, result < 0) << "waitpid() failed";
   return FALSE;  // Don't call this callback again
 }
 }  // namespace
 
 void ScheduleCrashReporterUpload() {
-  g_idle_add(&TriggerCrashReporterUpload, NULL);
+  g_idle_add(&TriggerCrashReporterUpload, nullptr);
 }
 
 bool SetCpuShares(CpuShares shares) {
@@ -1401,7 +1402,7 @@
        i != vector.end(); ++i) {
     g_ptr_array_add(p, g_strdup(i->c_str()));
   }
-  g_ptr_array_add(p, NULL);
+  g_ptr_array_add(p, nullptr);
   return reinterpret_cast<gchar**>(g_ptr_array_free(p, FALSE));
 }
 
@@ -1477,7 +1478,7 @@
   }
 
   FILE *file = base::CreateAndOpenTemporaryFile(out_path);
-  if (file == NULL) {
+  if (file == nullptr) {
     LOG(ERROR) << "Error creating temporary file.";
     return false;
   }
diff --git a/utils.h b/utils.h
index 6d14fbc..a526ccd 100644
--- a/utils.h
+++ b/utils.h
@@ -37,7 +37,7 @@
 // down.
 base::Time TimeFromStructTimespec(struct timespec *ts);
 
-// Converts a vector of strings to a NULL-terminated array of
+// Converts a vector of strings to a NUL-terminated array of
 // strings. The resulting array should be freed with g_strfreev()
 // when are you done with it.
 gchar** StringVectorToGStrv(const std::vector<std::string> &vector);
@@ -114,9 +114,9 @@
 // "../"), then it is prepended the value of TMPDIR, which defaults to /tmp if
 // it isn't set or is empty.  It then calls mkstemp(3) with the resulting
 // template.  Writes the name of a new temporary file to |filename|. If |fd| is
-// non-NULL, the file descriptor returned by mkstemp is written to it and kept
-// open; otherwise, it is closed. The template must end with "XXXXXX". Returns
-// true on success.
+// non-null, the file descriptor returned by mkstemp is written to it and
+// kept open; otherwise, it is closed. The template must end with "XXXXXX".
+// Returns true on success.
 bool MakeTempFile(const std::string& base_filename_template,
                   std::string* filename,
                   int* fd);
@@ -149,7 +149,7 @@
 // number. For example, "/dev/sda3" will be split into {"/dev/sda", 3} and
 // "/dev/mmcblk0p2" into {"/dev/mmcblk0", 2}
 // Returns false when malformed device name is passed in.
-// If both output parameters are omitted (nullptr), can be used
+// If both output parameters are omitted (null), can be used
 // just to test the validity of the device name. Note that the function
 // simply checks if the device name looks like a valid device, no other
 // checks are performed (i.e. it doesn't check if the device actually exists).
@@ -363,12 +363,12 @@
 std::string CodeToString(ErrorCode code);
 
 // Creates the powerwash marker file with the appropriate commands in it.  Uses
-// |file_path| as the path to the marker file if non-NULL, otherwise uses the
+// |file_path| as the path to the marker file if non-null, otherwise uses the
 // global default. Returns true if successfully created.  False otherwise.
 bool CreatePowerwashMarkerFile(const char* file_path);
 
 // Deletes the marker file used to trigger Powerwash using clobber-state.  Uses
-// |file_path| as the path to the marker file if non-NULL, otherwise uses the
+// |file_path| as the path to the marker file if non-null, otherwise uses the
 // global default. Returns true if successfully deleted. False otherwise.
 bool DeletePowerwashMarkerFile(const char* file_path);
 
diff --git a/utils_unittest.cc b/utils_unittest.cc
index f23dd5c..4618beb 100644
--- a/utils_unittest.cc
+++ b/utils_unittest.cc
@@ -315,9 +315,9 @@
 
 TEST(UtilsTest, RunAsRootGetFilesystemSizeTest) {
   string img;
-  EXPECT_TRUE(utils::MakeTempFile("img.XXXXXX", &img, NULL));
+  EXPECT_TRUE(utils::MakeTempFile("img.XXXXXX", &img, nullptr));
   ScopedPathUnlinker img_unlinker(img);
-  CreateExtImageAtPath(img, NULL);
+  CreateExtImageAtPath(img, nullptr);
   // Extend the "partition" holding the file system from 10MiB to 20MiB.
   EXPECT_EQ(0, System(base::StringPrintf(
       "dd if=/dev/zero of=%s seek=20971519 bs=1 count=1",