diff --git a/policy_manager/all_variables.h b/policy_manager/all_variables.h
index be77698..fb3401e 100644
--- a/policy_manager/all_variables.h
+++ b/policy_manager/all_variables.h
@@ -7,11 +7,14 @@
 
 // List of globally available variables exposed by the different providers.
 //
-// Each state provider should implement a header file with the suffix "_vars.h"
-// with all the defined variable pointers, such as:
-//  Variable<MyType>* var_something;
-// This file includes all the different provider's header files with these
-// definitions.
+// Each state provider must implement a header file with the suffix "_vars.h",
+// which declares all the variables owned by this provider declared as extern
+// global pointers.
+//
+//   extern Variable<SomeType>* var_providername_variablename;
+//
+// This file is just an aggregate of all variable declarations
+// from the different providers.
 
 #include "policy_manager/random_vars.h"
 
diff --git a/policy_manager/generic_variables-inl.h b/policy_manager/generic_variables-inl.h
deleted file mode 100644
index f44a287..0000000
--- a/policy_manager/generic_variables-inl.h
+++ /dev/null
@@ -1,21 +0,0 @@
-// Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_GENERIC_VARIABLES_INL_H
-#define CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_GENERIC_VARIABLES_INL_H
-
-namespace chromeos_policy_manager {
-
-template<typename T>
-CopyVariable<T>::CopyVariable(const T& ref) : ref_(ref) {}
-
-template<typename T>
-const T* CopyVariable<T>::GetValue(base::TimeDelta /* timeout */,
-                                   std::string* /* errmsg */) {
-  return new T(ref_);
-};
-
-}  // namespace chromeos_policy_manager
-
-#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_GENERIC_VARIABLES_INL_H
diff --git a/policy_manager/generic_variables.h b/policy_manager/generic_variables.h
index 321c89a..e78bbbd 100644
--- a/policy_manager/generic_variables.h
+++ b/policy_manager/generic_variables.h
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Generic and provider independent Variable subclasses. These variables can be
+// Generic and provider-independent Variable subclasses. These variables can be
 // used by any state provider to implement simple variables to avoid repeat the
 // same common code on different state providers.
 
@@ -19,24 +19,17 @@
 // create copies of the provided object using the copy constructor of that
 // class.
 //
-// For example, a state provider exposing a private method as a variable could
-// be implemented in this way:
+// For example, a state provider exposing a private member as a variable can
+// implement this as follows:
 //
-// * On something_vars.h:
-//   Variable<MyType>* var_something;
-//
-// * On something_provider:
 //   class SomethingProvider {
 //    public:
 //      SomethingProvider(...) {
-//        var_something = new CopyVariable<MyType>(priv_object_);
+//        var_something_foo = new CopyVariable<MyType>(foo_);
 //      }
-//      ~SomethingProvider() {
-//        delete var_something;
-//        var_something = NULL;
-//      }
+//      ...
 //    private:
-//     MyType priv_object_;
+//     MyType foo_;
 //   };
 template<typename T>
 class CopyVariable : public Variable<T> {
@@ -44,17 +37,20 @@
   // Creates the variable returning copies of the passed |obj| reference. The
   // reference to this object is kept and it should be available whenever the
   // GetValue() method is called.
-  CopyVariable(const T& obj);
+  CopyVariable(const T& ref) : ref_(ref) {};
 
   virtual ~CopyVariable() {}
 
  protected:
-  friend class PMCopyVariableTest;
-  FRIEND_TEST(PMCopyVariableTest, SimpleTest);
-  FRIEND_TEST(PMCopyVariableTest, UseCopyConstructorTest);
+  friend class PmCopyVariableTest;
+  FRIEND_TEST(PmCopyVariableTest, SimpleTest);
+  FRIEND_TEST(PmCopyVariableTest, UseCopyConstructorTest);
 
   // Variable override.
-  virtual const T* GetValue(base::TimeDelta timeout, std::string* errmsg);
+  virtual const T* GetValue(base::TimeDelta /* timeout */,
+                            std::string* /* errmsg */) {
+    return new T(ref_);
+  }
 
  private:
   // Reference to the object to be copied by GetValue().
@@ -63,7 +59,4 @@
 
 }  // namespace chromeos_policy_manager
 
-// Include implementation on header files for templates.
-#include "policy_manager/generic_variables-inl.h"
-
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_GENERIC_VARIABLES_H
diff --git a/policy_manager/generic_variables_unittest.cc b/policy_manager/generic_variables_unittest.cc
index 6758e23..14b40d3 100644
--- a/policy_manager/generic_variables_unittest.cc
+++ b/policy_manager/generic_variables_unittest.cc
@@ -10,7 +10,7 @@
 
 namespace chromeos_policy_manager {
 
-TEST(PMCopyVariableTest, SimpleTest) {
+TEST(PmCopyVariableTest, SimpleTest) {
   int obj_int = 5;
 
   CopyVariable<int> var(obj_int);
@@ -45,7 +45,7 @@
   bool copied_;
 };
 
-TEST(PMCopyVariableTest, UseCopyConstructorTest) {
+TEST(PmCopyVariableTest, UseCopyConstructorTest) {
   ConstructorTestClass obj;
   ASSERT_FALSE(obj.copied_);
 
diff --git a/policy_manager/provider.h b/policy_manager/provider.h
new file mode 100644
index 0000000..0081c0d
--- /dev/null
+++ b/policy_manager/provider.h
@@ -0,0 +1,35 @@
+// Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_PM_PROVIDER_H
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_PM_PROVIDER_H
+
+namespace chromeos_policy_manager {
+
+// Abstract base class for a policy provider.
+class Provider {
+ public:
+  Provider() : is_initialized_(false) {}
+  virtual ~Provider() {}
+
+  // Initializes the provider at most once.  Returns true on success.
+  bool Init() {
+    return is_initialized_ || (is_initialized_ = DoInit());
+  }
+
+ protected:
+  // Performs the actual initialization. To be implemented by concrete
+  // subclasses.
+  virtual bool DoInit() = 0;
+
+ private:
+  // Whether the provider was already initialized.
+  bool is_initialized_;
+
+  DISALLOW_COPY_AND_ASSIGN(Provider);
+};
+
+}  // namespace chromeos_policy_manager
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_PM_PROVIDER_H
diff --git a/policy_manager/random_provider.cc b/policy_manager/random_provider.cc
index f2373b0..70dc31b 100644
--- a/policy_manager/random_provider.cc
+++ b/policy_manager/random_provider.cc
@@ -62,11 +62,14 @@
 
 // RandomProvider implementation.
 
-bool RandomProvider::Init(void) {
-  // Check for double Init()
-  if (var_random_seed != NULL)
-    return false;
+RandomProvider::~RandomProvider(void) {
+  if (var_random_seed) {
+    delete var_random_seed;
+    var_random_seed = NULL;
+  }
+}
 
+bool RandomProvider::DoInit(void) {
   FILE* fp = fopen(kRandomDevice, "r");
   if (!fp)
     return false;
@@ -74,11 +77,4 @@
   return true;
 }
 
-void RandomProvider::Finalize(void) {
-  if (var_random_seed) {
-    delete var_random_seed;
-    var_random_seed = NULL;
-  }
-}
-
 }  // namespace chromeos_policy_manager
diff --git a/policy_manager/random_provider.h b/policy_manager/random_provider.h
index 7c7bae9..a610786 100644
--- a/policy_manager/random_provider.h
+++ b/policy_manager/random_provider.h
@@ -5,21 +5,18 @@
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_PM_RANDOM_PROVIDER_H
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_PM_RANDOM_PROVIDER_H
 
-#include "base/basictypes.h"
+#include "policy_manager/provider.h"
 
 namespace chromeos_policy_manager {
 
 // Provider of random values.
-class RandomProvider {
+class RandomProvider : public Provider {
  public:
   RandomProvider() {}
+  virtual ~RandomProvider();
 
-  // Initialize the provider variables and internal state. Returns whether it
-  // succeeded.
-  bool Init();
-
-  // Destroy all the provider variables in a best-effor approach.
-  void Finalize();
+ protected:
+  virtual bool DoInit();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(RandomProvider);
diff --git a/policy_manager/random_provider_unittest.cc b/policy_manager/random_provider_unittest.cc
index 82ee5cc..af11b6e 100644
--- a/policy_manager/random_provider_unittest.cc
+++ b/policy_manager/random_provider_unittest.cc
@@ -14,44 +14,47 @@
 
 namespace chromeos_policy_manager {
 
-class PMRandomProviderTest : public ::testing::Test {
+class PmRandomProviderTest : public ::testing::Test {
  protected:
   virtual void SetUp() {
     ASSERT_TRUE(var_random_seed == NULL);
-    EXPECT_TRUE(provider_.Init());
+    provider_ = new RandomProvider();
+    ASSERT_TRUE(provider_);
+    EXPECT_TRUE(provider_->Init());
   }
 
   virtual void TearDown() {
-    provider_.Finalize();
+    delete provider_;
+    provider_ = NULL;
     ASSERT_TRUE(var_random_seed == NULL);
   }
 
  private:
-  RandomProvider provider_;
+  RandomProvider* provider_;
 };
 
-TEST_F(PMRandomProviderTest, InitFinalize) {
+TEST_F(PmRandomProviderTest, InitFinalize) {
   // The provider should initialize the variable with a valid object.
   ASSERT_TRUE(var_random_seed != NULL);
 }
 
-TEST_F(PMRandomProviderTest, GetRandomValues) {
+TEST_F(PmRandomProviderTest, GetRandomValues) {
   string errmsg;
   scoped_ptr<const uint64> value(
       var_random_seed->GetValue(TimeDelta::FromSeconds(1.), &errmsg));
   ASSERT_TRUE(value != NULL);
 
-  bool returns_allways_the_same_value = true;
+  bool always_returns_the_same_value = true;
   // Test that at least the returned values are different. This test fails,
   // by design, once every 2^320 runs.
   for (int i = 0; i < 5; i++) {
     scoped_ptr<const uint64> other_value(
         var_random_seed->GetValue(TimeDelta::FromSeconds(1.), &errmsg));
     ASSERT_TRUE(other_value != NULL);
-    returns_allways_the_same_value = returns_allways_the_same_value &&
+    always_returns_the_same_value = always_returns_the_same_value &&
         *other_value == *value;
   }
-  EXPECT_FALSE(returns_allways_the_same_value);
+  EXPECT_FALSE(always_returns_the_same_value);
 }
 
 }  // namespace chromeos_policy_manager
diff --git a/policy_manager/random_vars.h b/policy_manager/random_vars.h
index c1563c5..d983ca1 100644
--- a/policy_manager/random_vars.h
+++ b/policy_manager/random_vars.h
@@ -6,6 +6,7 @@
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_PM_RANDOM_VARS_H
 
 #include "base/basictypes.h"
+
 #include "policy_manager/variable.h"
 
 namespace chromeos_policy_manager {
diff --git a/policy_manager/variable.h b/policy_manager/variable.h
index 6acd31f..79953ed 100644
--- a/policy_manager/variable.h
+++ b/policy_manager/variable.h
@@ -19,8 +19,8 @@
   virtual ~Variable() {}
 
  protected:
-  friend class PMRandomProviderTest;
-  FRIEND_TEST(PMRandomProviderTest, GetRandomValues);
+  friend class PmRandomProviderTest;
+  FRIEND_TEST(PmRandomProviderTest, GetRandomValues);
 
   // Gets the current value of the variable. The current value is copied to a
   // new object and returned. The caller of this method owns the object and