Bug 1284177 - P1: Provide observable notification for video suspend. r=jwwang

To support mochitests, report change in video decode suspend state via
events mozentervideosuspend/mozexitvideosuspend.

MozReview-Commit-ID: EwMduLzcMVg

--HG--
extra : rebase_source : 5f1fed90964fae182f06d9fb480491728c5f1c97

dom/media/MediaDecoder.cpp

@@ -697,6 +697,12 @@ MediaDecoder::OnPlaybackEvent(MediaEventType aEvent)
     case MediaEventType::Invalidate:
       Invalidate();
       break;
+    case MediaEventType::EnterVideoSuspend:
+      mOwner->DispatchAsyncEvent(NS_LITERAL_STRING("mozentervideosuspend"));
+      break;
+    case MediaEventType::ExitVideoSuspend:
+      mOwner->DispatchAsyncEvent(NS_LITERAL_STRING("mozexitvideosuspend"));
+      break;
   }
 }
 

dom/media/MediaDecoderStateMachine.cpp

@@ -1328,8 +1328,8 @@ void MediaDecoderStateMachine::VisibilityChanged()
 {
   MOZ_ASSERT(OnTaskQueue());
   DECODER_LOG("VisibilityChanged: mIsVisible=%d, "
-              "mVideoDecodeSuspended=%d, mIsReaderSuspended=%d",
-              mIsVisible.Ref(), mVideoDecodeSuspended, mIsReaderSuspended.Ref());
+              "mVideoDecodeSuspended=%c, mIsReaderSuspended=%d",
+              mIsVisible.Ref(), mVideoDecodeSuspended ? 'T' : 'F', mIsReaderSuspended.Ref());
 
   if (!HasVideo()) {
     return;
@@ -1358,6 +1358,7 @@ void MediaDecoderStateMachine::VisibilityChanged()
 
   if (mVideoDecodeSuspended) {
     mVideoDecodeSuspended = false;
+    mOnPlaybackEvent.Notify(MediaEventType::ExitVideoSuspend);
     mReader->SetVideoBlankDecode(false);
 
     if (mIsReaderSuspended) {
@@ -2931,6 +2932,7 @@ MediaDecoderStateMachine::OnSuspendTimerResolved()
   DECODER_LOG("OnSuspendTimerResolved");
   mVideoDecodeSuspendTimer.CompleteRequest();
   mVideoDecodeSuspended = true;
+  mOnPlaybackEvent.Notify(MediaEventType::EnterVideoSuspend);
   mReader->SetVideoBlankDecode(true);
 }
 

dom/media/MediaDecoderStateMachine.h

@@ -120,7 +120,9 @@ enum class MediaEventType : int8_t {
   PlaybackEnded,
   SeekStarted,
   DecodeError,
-  Invalidate
+  Invalidate,
+  EnterVideoSuspend,
+  ExitVideoSuspend
 };
 
 /*