Bug 1390748 - Create default MediaDecoder::GetMozDebugReaderData() implementation. r=jwwang

We have three implementations, in the MP4, WebM and MediaSource decoders.  The
WebM and MP4 are the same. Ogg and other decoders don't have an implementation,
but if we create a default implementation in MediaDecoder, they'll get it for
free. MediaSourceDecoder needs a custom override still.

MozReview-Commit-ID: AXxn2Xhn0Jn

--HG--
extra : rebase_source : 83d0facbe26f8385c7163dc85d5512e7a43e80f4

dom/media/MediaDecoder.cpp

@@ -1621,6 +1621,14 @@ MediaDecoder::RequestDebugInfo()
     });
 }
 
+void
+MediaDecoder::GetMozDebugReaderData(nsACString& aString)
+{
+  if (mReader) {
+    mReader->GetMozDebugReaderData(aString);
+  }
+}
+
 void
 MediaDecoder::NotifyAudibleStateChanged()
 {

dom/media/MediaDecoder.h

@@ -406,7 +406,7 @@ private:
 
   // Returns a string describing the state of the media player internal
   // data. Used for debugging purposes.
-  virtual void GetMozDebugReaderData(nsACString& aString) { }
+  virtual void GetMozDebugReaderData(nsACString& aString);
 
   virtual void DumpDebugInfo();
 

dom/media/fmp4/MP4Decoder.cpp

@@ -278,12 +278,4 @@ MP4Decoder::IsVideoAccelerated(layers::KnowsCompositor* aKnowsCompositor, nsIGlo
   return promise.forget();
 }
 
-void
-MP4Decoder::GetMozDebugReaderData(nsACString& aString)
-{
-  if (mReader) {
-    mReader->GetMozDebugReaderData(aString);
-  }
-}
-
 } // namespace mozilla

dom/media/fmp4/MP4Decoder.h

@@ -42,8 +42,6 @@ public:
   static already_AddRefed<dom::Promise>
   IsVideoAccelerated(layers::KnowsCompositor* aKnowsCompositor, nsIGlobalObject* aParent);
 
-  void GetMozDebugReaderData(nsACString& aString) override;
-
 private:
   ChannelMediaDecoder* CloneImpl(MediaDecoderInit& aInit) override
   {

dom/media/webm/WebMDecoder.cpp

@@ -58,13 +58,5 @@ WebMDecoder::IsSupportedType(const MediaContainerType& aContainerType)
   return true;
 }
 
-void
-WebMDecoder::GetMozDebugReaderData(nsACString& aString)
-{
-  if (mReader) {
-    mReader->GetMozDebugReaderData(aString);
-  }
-}
-
 } // namespace mozilla
 

dom/media/webm/WebMDecoder.h

@@ -25,8 +25,6 @@ public:
   // If provided, codecs are checked for support.
   static bool IsSupportedType(const MediaContainerType& aContainerType);
 
-  void GetMozDebugReaderData(nsACString& aString) override;
-
 private:
   ChannelMediaDecoder* CloneImpl(MediaDecoderInit& aInit) override
   {