Bug 1125776: Part8. We don't always need an init segment to be ready. r=mattwoodrow

If abort was called on the source buffer, the parser would have been reset.
The content in the Track Buffer is still valid for playback.

dom/media/mediasource/TrackBuffer.cpp

@@ -691,7 +691,7 @@ TrackBuffer::IsReady()
 {
   ReentrantMonitorAutoEnter mon(mParentDecoder->GetReentrantMonitor());
   MOZ_ASSERT((mInfo.HasAudio() || mInfo.HasVideo()) || mInitializedDecoders.IsEmpty());
-  return mParser->HasInitData() && (mInfo.HasAudio() || mInfo.HasVideo());
+  return mInfo.HasAudio() || mInfo.HasVideo();
 }
 
 bool