Bug 1219142. Part 1 - add AbstractMediaDecoder::DataArrivedEvent() to publish events. r=jya.

dom/media/AbstractMediaDecoder.h

@@ -10,6 +10,7 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/StateMirroring.h"
 
+#include "MediaEventSource.h"
 #include "MediaInfo.h"
 #include "nsISupports.h"
 #include "nsDataHashtable.h"
@@ -68,6 +69,15 @@ public:
 
   virtual AbstractCanonical<media::NullableTimeUnit>* CanonicalDurationOrNull() { return nullptr; };
 
+  // Return an event that will be notified when data arrives in MediaResource.
+  // MediaDecoderReader will register with this event to receive notifications
+  // in order to udpate buffer ranges.
+  // Return null if this decoder doesn't support the event.
+  virtual MediaEventSource<void>* DataArrivedEvent()
+  {
+    return nullptr;
+  }
+
 protected:
   virtual void UpdateEstimatedMediaDuration(int64_t aDuration) {};
 public:

dom/media/MediaDecoder.cpp

@@ -1447,10 +1447,13 @@ void
 MediaDecoder::NotifyDataArrived() {
   MOZ_ASSERT(NS_IsMainThread());
 
-  if (mDecoderStateMachine) {
-    mDecoderStateMachine->DispatchNotifyDataArrived();
+  // Don't publish events since task queues might be shutting down.
+  if (mShuttingDown) {
+    return;
   }
 
+  mDataArrivedEvent.Notify();
+
   // ReadyState computation depends on MediaDecoder::CanPlayThrough, which
   // depends on the download rate.
   UpdateReadyState();

dom/media/MediaDecoder.h

@@ -820,6 +820,11 @@ protected:
   RefPtr<MediaResource> mResource;
 
 private:
+  MediaEventSource<void>*
+  DataArrivedEvent() override { return &mDataArrivedEvent; }
+
+  MediaEventProducer<void> mDataArrivedEvent;
+
   // The state machine object for handling the decoding. It is safe to
   // call methods of this object from other threads. Its internal data
   // is synchronised on a monitor. The lifetime of this object is

dom/media/MediaDecoderReader.cpp

@@ -79,6 +79,11 @@ MediaDecoderReader::MediaDecoderReader(AbstractMediaDecoder* aDecoder)
   MOZ_COUNT_CTOR(MediaDecoderReader);
   MOZ_ASSERT(NS_IsMainThread());
 
+  if (mDecoder && mDecoder->DataArrivedEvent()) {
+    mDataArrivedListener = mDecoder->DataArrivedEvent()->Connect(
+      mTaskQueue, this, &MediaDecoderReader::NotifyDataArrived);
+  }
+
   // Dispatch initialization that needs to happen on that task queue.
   nsCOMPtr<nsIRunnable> r = NS_NewRunnableMethod(this, &MediaDecoderReader::InitializationTask);
   mTaskQueue->Dispatch(r.forget());
@@ -360,6 +365,8 @@ MediaDecoderReader::Shutdown()
   mBaseAudioPromise.RejectIfExists(END_OF_STREAM, __func__);
   mBaseVideoPromise.RejectIfExists(END_OF_STREAM, __func__);
 
+  mDataArrivedListener.DisconnectIfExists();
+
   ReleaseMediaResources();
   mDuration.DisconnectIfConnected();
   mBuffered.DisconnectAll();

dom/media/MediaDecoderReader.h

@@ -428,6 +428,8 @@ private:
   // "discontinuity" in the stream. For example after a seek.
   bool mAudioDiscontinuity;
   bool mVideoDiscontinuity;
+
+  MediaEventListener mDataArrivedListener;
 };
 
 } // namespace mozilla