Bug 778682. Part 1: Add NotifyHasCurrentData callback on StreamListener. r=jesup

--HG--
extra : rebase_source : a56fe8ba36639da7638eb590bd9a7a7e65efae95

content/media/MediaStreamGraph.cpp

@@ -294,6 +294,10 @@ public:
    * Get the current audio position of the stream's audio output.
    */
   GraphTime GetAudioPosition(MediaStream* aStream);
+  /**
+   * Call NotifyHaveCurrentData on aStream's listeners.
+   */
+  void NotifyHasCurrentData(MediaStream* aStream);
   /**
    * If aStream needs an audio stream but doesn't have one, create it.
    * If aStream doesn't need an audio stream but has one, destroy it.
@@ -1106,6 +1110,16 @@ MediaStreamGraphImpl::RecomputeBlockingAt(const nsTArray<MediaStream*>& aStreams
   }
 }
 
+void
+MediaStreamGraphImpl::NotifyHasCurrentData(MediaStream* aStream)
+{
+  for (uint32_t j = 0; j < aStream->mListeners.Length(); ++j) {
+    MediaStreamListener* l = aStream->mListeners[j];
+    l->NotifyHasCurrentData(this,
+      GraphTimeToStreamTime(aStream, mCurrentTime) < aStream->mBuffer.GetEnd());
+  }
+}
+
 void
 MediaStreamGraphImpl::CreateOrDestroyAudioStreams(GraphTime aAudioOutputStartTime,
                                                   MediaStream* aStream)
@@ -1397,6 +1411,7 @@ MediaStreamGraphImpl::RunThread()
                      GraphTimeToStreamTime(stream, mStateComputedTime),
                      "Stream did not produce enough data");
       }
+      NotifyHasCurrentData(stream);
       CreateOrDestroyAudioStreams(prevComputedTime, stream);
       PlayAudio(stream, prevComputedTime, mStateComputedTime);
       audioStreamsActive += stream->mAudioOutputStreams.Length();

content/media/MediaStreamGraph.h

@@ -127,6 +127,12 @@ public:
    */
   virtual void NotifyBlockingChanged(MediaStreamGraph* aGraph, Blocking aBlocked) {}
 
+  /**
+   * Notify that the stream has (or does not have) data in each track
+   * for the stream's current time.
+   */
+  virtual void NotifyHasCurrentData(MediaStreamGraph* aGraph, bool aHasCurrentData) {}
+
   /**
    * Notify that the stream output is advancing.
    */