Bug 1272930 - Fix some -Wshadow warnings in dom/media/systemservices. r=gerald

dom/media/systemservices/MediaSystemResourceManager.cpp:71:33 [-Wshadow] declaration shadows a local variable
dom/media/systemservices/MediaUtils.h:85:32 [-Wshadow] declaration shadows a local variable
dom/media/systemservices/MediaUtils.h:85:60 [-Wshadow] declaration shadows a local variable
dom/media/systemservices/MediaParent.cpp:250:19 [-Wshadow-local] declaration of 'buffer' shadows a previous local
dom/media/systemservices/MediaParent.cpp:258:18 [-Wshadow-compatible-local] declaration of 'count' shadows a previous local
dom/media/systemservices/MediaParent.cpp:259:18 [-Wshadow-compatible-local] declaration of 'rv' shadows a previous local

dom/media/systemservices/MediaParent.cpp

@@ -228,16 +228,17 @@ class OriginKeyStore : public nsISupports
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
-      nsAutoCString buffer;
-      buffer.AppendLiteral(ORIGINKEYS_VERSION);
-      buffer.Append('\n');
+
+      nsAutoCString versionBuffer;
+      versionBuffer.AppendLiteral(ORIGINKEYS_VERSION);
+      versionBuffer.Append('\n');
 
       uint32_t count;
-      rv = stream->Write(buffer.Data(), buffer.Length(), &count);
+      rv = stream->Write(versionBuffer.Data(), versionBuffer.Length(), &count);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
-      if (count != buffer.Length()) {
+      if (count != versionBuffer.Length()) {
         return NS_ERROR_UNEXPECTED;
       }
       for (auto iter = mKeys.Iter(); !iter.Done(); iter.Next()) {
@@ -247,17 +248,17 @@ class OriginKeyStore : public nsISupports
         if (!originKey->mSecondsStamp) {
           continue; // don't write temporal ones
         }
-        nsCString buffer;
-        buffer.Append(originKey->mKey);
-        buffer.Append(' ');
-        buffer.AppendInt(originKey->mSecondsStamp);
-        buffer.Append(' ');
-        buffer.Append(origin);
-        buffer.Append('\n');
 
-        uint32_t count;
-        nsresult rv = stream->Write(buffer.Data(), buffer.Length(), &count);
-        if (NS_WARN_IF(NS_FAILED(rv)) || count != buffer.Length()) {
+        nsCString originBuffer;
+        originBuffer.Append(originKey->mKey);
+        originBuffer.Append(' ');
+        originBuffer.AppendInt(originKey->mSecondsStamp);
+        originBuffer.Append(' ');
+        originBuffer.Append(origin);
+        originBuffer.Append('\n');
+
+        rv = stream->Write(originBuffer.Data(), originBuffer.Length(), &count);
+        if (NS_WARN_IF(NS_FAILED(rv)) || count != originBuffer.Length()) {
           break;
         }
       }

dom/media/systemservices/MediaSystemResourceManager.cpp

@@ -60,7 +60,7 @@ MediaSystemResourceManager::Init()
   }
 
   ReentrantMonitor barrier("MediaSystemResourceManager::Init");
-  ReentrantMonitorAutoEnter autoMon(barrier);
+  ReentrantMonitorAutoEnter mainThreadAutoMon(barrier);
   bool done = false;
 
   RefPtr<Runnable> runnable =
@@ -68,7 +68,7 @@ MediaSystemResourceManager::Init()
       if (!sSingleton) {
         sSingleton = new MediaSystemResourceManager();
       }
-      ReentrantMonitorAutoEnter autoMon(barrier);
+      ReentrantMonitorAutoEnter childThreadAutoMon(barrier);
       done = true;
       barrier.NotifyAll();
     });
@@ -79,7 +79,6 @@ MediaSystemResourceManager::Init()
   while (!done) {
     barrier.Wait();
   }
-
 }
 
 MediaSystemResourceManager::MediaSystemResourceManager()

dom/media/systemservices/MediaUtils.h

@@ -82,8 +82,8 @@ public:
     class Functors : public FunctorsBase
     {
     public:
-      Functors(OnSuccessType&& aOnSuccess, OnFailureType&& aOnFailure)
-        : mOnSuccess(Move(aOnSuccess)), mOnFailure(Move(aOnFailure)) {}
+      Functors(OnSuccessType&& aOnSuccessRef, OnFailureType&& aOnFailureRef)
+        : mOnSuccess(Move(aOnSuccessRef)), mOnFailure(Move(aOnFailureRef)) {}
 
       void Succeed(ValueType& result)
       {