MediaMetrics: Fix clang-tidy warnings

Test: atest mediametrics_tests
Bug: 153658358
Change-Id: Ic3c05de5466df24ffd37b224c97ac1138257a73c
diff --git a/media/libmediametrics/include/media/MediaMetricsItem.h b/media/libmediametrics/include/media/MediaMetricsItem.h
index 591e714..8477f8d 100644
--- a/media/libmediametrics/include/media/MediaMetricsItem.h
+++ b/media/libmediametrics/include/media/MediaMetricsItem.h
@@ -223,7 +223,7 @@
 class Defer {
 public:
     template <typename U>
-    Defer(U &&f) : mThunk(std::forward<U>(f)) {}
+    explicit Defer(U &&f) : mThunk(std::forward<U>(f)) {}
     ~Defer() { mThunk(); }
 
 private:
@@ -522,7 +522,7 @@
     BufferedItem(const BufferedItem&) = delete;
     BufferedItem& operator=(const BufferedItem&) = delete;
 
-    BufferedItem(const std::string key, char *begin, char *end)
+    BufferedItem(const std::string& key, char *begin, char *end)
         : BufferedItem(key.c_str(), begin, end) { }
 
     BufferedItem(const char *key, char *begin, char *end)
@@ -687,7 +687,7 @@
 template <size_t N = 4096>
 class LogItem : public BufferedItem {
 public:
-    explicit LogItem(const std::string key) : LogItem(key.c_str()) { }
+    explicit LogItem(const std::string& key) : LogItem(key.c_str()) { }
 
     // Since this class will not be defined before the base class, we initialize variables
     // in our own order.
@@ -742,10 +742,10 @@
             mElem = other.mElem;
             return *this;
         }
-        Prop(Prop&& other) {
+        Prop(Prop&& other) noexcept {
             *this = std::move(other);
         }
-        Prop& operator=(Prop&& other) {
+        Prop& operator=(Prop&& other) noexcept {
             mName = std::move(other.mName);
             mElem = std::move(other.mElem);
             return *this;
@@ -856,7 +856,7 @@
     // Iteration of props within item
     class iterator {
     public:
-        iterator(const std::map<std::string, Prop>::const_iterator &_it) : it(_it) { }
+        explicit iterator(const std::map<std::string, Prop>::const_iterator &_it) : it(_it) { }
         iterator &operator++() {
             ++it;
             return *this;
diff --git a/services/mediametrics/AnalyticsState.h b/services/mediametrics/AnalyticsState.h
index e8fedcf..b648947 100644
--- a/services/mediametrics/AnalyticsState.h
+++ b/services/mediametrics/AnalyticsState.h
@@ -98,7 +98,7 @@
         }
         if (ll > 0) {
             auto [s, l] = mTransactionLog.dump(ll, sinceNs, prefix);
-            ss << std::move(s);
+            ss << s;
             ll -= l;
         }
         if (ll > 0) {
@@ -107,7 +107,7 @@
         }
         if (ll > 0) {
             auto [s, l] = mTimeMachine.dump(ll, sinceNs, prefix);
-            ss << std::move(s);
+            ss << s;
             ll -= l;
         }
         return { ss.str(), lines - ll };
diff --git a/services/mediametrics/AudioAnalytics.cpp b/services/mediametrics/AudioAnalytics.cpp
index f80516e..3f9a42f 100644
--- a/services/mediametrics/AudioAnalytics.cpp
+++ b/services/mediametrics/AudioAnalytics.cpp
@@ -115,7 +115,7 @@
 
     if (ll > 0) {
         auto [s, l] = mAnalyticsState->dump(ll, sinceNs, prefix);
-        ss << std::move(s);
+        ss << s;
         ll -= l;
     }
     if (ll > 0) {
@@ -124,7 +124,7 @@
     }
     if (ll > 0) {
         auto [s, l] = mPreviousAnalyticsState->dump(ll, sinceNs, prefix);
-        ss << std::move(s);
+        ss << s;
         ll -= l;
     }
     return { ss.str(), lines - ll };
diff --git a/services/mediametrics/TimeMachine.h b/services/mediametrics/TimeMachine.h
index 75819ba..29adeae 100644
--- a/services/mediametrics/TimeMachine.h
+++ b/services/mediametrics/TimeMachine.h
@@ -152,7 +152,7 @@
                 std::string s = dump(mKey, tsPair, time);
                 if (s.size() > 0) {
                     --ll;
-                    ss << std::move(s);
+                    ss << s;
                 }
             }
             return { ss.str(), lines - ll };
@@ -319,7 +319,7 @@
                 if (it == mHistory.end()) continue;
                 remoteKeyHistory = it->second;
             }
-            std::lock_guard(getLockForKey(remoteKey));
+            std::lock_guard lock(getLockForKey(remoteKey));
             remoteKeyHistory->putProp(remoteName, prop, time);
         }
         return NO_ERROR;
@@ -426,7 +426,7 @@
             if (prefix != nullptr && !startsWith(it->first, prefix)) break;
             std::lock_guard lock(getLockForKey(it->first));
             auto [s, l] = it->second->dump(ll, sinceNs);
-            ss << std::move(s);
+            ss << s;
             ll -= l;
         }
         return { ss.str(), lines - ll };
@@ -441,7 +441,7 @@
 
     // Finds a KeyHistory from a URL.  Returns nullptr if not found.
     std::shared_ptr<KeyHistory> getKeyHistoryFromUrl(
-            std::string url, std::string* key, std::string *prop) const {
+            const std::string& url, std::string* key, std::string *prop) const {
         std::lock_guard lock(mLock);
 
         auto it = mHistory.upper_bound(url);
diff --git a/services/mediametrics/TransactionLog.h b/services/mediametrics/TransactionLog.h
index 2359eec..4f09bb0 100644
--- a/services/mediametrics/TransactionLog.h
+++ b/services/mediametrics/TransactionLog.h
@@ -142,7 +142,7 @@
             --ll;
         }
         auto [s, l] = dumpMapTimeItem(mLog, ll, sinceNs, prefix);
-        ss << std::move(s);
+        ss << s;
         ll -= l;
 
         // Grouped by item key (category)
@@ -158,7 +158,7 @@
             if (prefix != nullptr && !startsWith(it->first, prefix)) break;
             auto [s, l] = dumpMapTimeItem(it->second, ll - 1, sinceNs, prefix);
             if (l == 0) continue; // don't show empty groups (due to sinceNs).
-            ss << " " << it->first << "\n" << std::move(s);
+            ss << " " << it->first << "\n" << s;
             ll -= l + 1;
         }
         return { ss.str(), lines - ll };
diff --git a/services/mediametrics/tests/mediametrics_tests.cpp b/services/mediametrics/tests/mediametrics_tests.cpp
index b8e566e..78eb71c 100644
--- a/services/mediametrics/tests/mediametrics_tests.cpp
+++ b/services/mediametrics/tests/mediametrics_tests.cpp
@@ -79,7 +79,7 @@
     const int mFinal;
 
     public:
-      Thunk(decltype(mF) f, int final) : mF(f), mFinal(final) {}
+      explicit Thunk(decltype(mF) f, int final) : mF(std::move(f)), mFinal(final) {}
       ~Thunk() { mF(mFinal); }
       void thunk(int value) { mF(value); }
   };
@@ -139,7 +139,7 @@
     std::function<void()> mF;
 
     public:
-      Thunk(decltype(mF) f) : mF(f) {}
+      explicit Thunk(decltype(mF) f) : mF(std::move(f)) {}
       void thunk() { mF(); }
   };