Bug 1310140. Part 10 - have SeekingState handle suspend-video-decoding. r=kaku,kamidphish

MozReview-Commit-ID: DRGfP3VN2OG

--HG--
extra : rebase_source : 6bca452d4612a1af4c929108dd9e21bf4d00465b
extra : source : a73b62cfa9b3dec2010c551a235affb7650603d4

dom/media/MediaDecoderStateMachine.cpp

@@ -629,6 +629,15 @@ public:
   {
     mSeekJob = Move(aSeekJob);
 
+    // Always switch off the blank decoder otherwise we might become visible
+    // in the middle of seeking and won't have a valid video frame to show
+    // when seek is done.
+    if (mMaster->mVideoDecodeSuspended) {
+      mMaster->mVideoDecodeSuspended = false;
+      mMaster->mOnPlaybackEvent.Notify(MediaEventType::ExitVideoSuspend);
+      Reader()->SetVideoBlankDecode(false);
+    }
+
     // SeekTask will register its callbacks to MediaDecoderReaderWrapper.
     mMaster->CancelMediaDecoderReaderWrapperCallback();
 
@@ -718,6 +727,11 @@ public:
 
   RefPtr<MediaDecoder::SeekPromise> HandleSeek(SeekTarget aTarget) override;
 
+  void HandleVideoSuspendTimeout() override
+  {
+    // Do nothing since we want a valid video frame to show when seek is done.
+  }
+
 private:
   void OnSeekTaskResolved(const SeekTaskResolveValue& aValue)
   {
@@ -2328,9 +2342,6 @@ void MediaDecoderStateMachine::VisibilityChanged()
   mVideoDecodeSuspendTimer.Reset();
 
   if (mVideoDecodeSuspended) {
-    mVideoDecodeSuspended = false;
-    mOnPlaybackEvent.Notify(MediaEventType::ExitVideoSuspend);
-    mReader->SetVideoBlankDecode(false);
 
     if (mIsReaderSuspended) {
       return;