Bug 1319706. Part 1 - remove DecodingFirstFrameState::mPendingSeek since it can handle seek requests immediately. r=kaku

MozReview-Commit-ID: I2lI63s46GQ

--HG--
extra : rebase_source : d702fbf9df841c18e3e1a239c6cc6226962f4550
extra : intermediate-source : 9d04eecdff11d055c2924b17c435b9b8aa1fb685
extra : source : ff0d8dde1bd4165f58f064d0320b042c922b0764

dom/media/MediaDecoderStateMachine.cpp

@@ -462,7 +462,7 @@ private:
  *
  * Transition to:
  *   SHUTDOWN if any decode error.
- *   SEEKING if any pending seek and seek is possible.
+ *   SEEKING if any seek request.
  *   DECODING when the 'loadeddata' event is fired.
  */
 class MediaDecoderStateMachine::DecodingFirstFrameState
@@ -473,13 +473,6 @@ public:
 
   void Enter(SeekJob aPendingSeek);
 
-  void Exit() override
-  {
-    // mPendingSeek is either moved before transition to SEEKING,
-    // or should be rejected here before transition to SHUTDOWN.
-    mPendingSeek.RejectIfExists(__func__);
-  }
-
   State GetState() const override
   {
     return DECODER_STATE_DECODING_FIRSTFRAME;
@@ -502,8 +495,6 @@ public:
     MaybeFinishDecodeFirstFrame();
   }
 
-  RefPtr<MediaDecoder::SeekPromise> HandleSeek(SeekTarget aTarget) override;
-
   void HandleVideoSuspendTimeout() override
   {
     // Do nothing for we need to decode the 1st video frame to get the dimensions.
@@ -519,8 +510,6 @@ private:
   // Notify FirstFrameLoaded if having decoded first frames and
   // transition to SEEKING if there is any pending seek, or DECODING otherwise.
   void MaybeFinishDecodeFirstFrame();
-
-  SeekJob mPendingSeek;
 };
 
 /**
@@ -1310,9 +1299,7 @@ MediaDecoderStateMachine::
 DecodingFirstFrameState::Enter(SeekJob aPendingSeek)
 {
   // Handle pending seek.
-  if (aPendingSeek.Exists() &&
-      (mMaster->mSentFirstFrameLoadedEvent ||
-       Reader()->ForceZeroStartTime())) {
+  if (aPendingSeek.Exists()) {
     SetState<SeekingState>(Move(aPendingSeek), EventVisibility::Observable);
     return;
   }
@@ -1325,34 +1312,10 @@ DecodingFirstFrameState::Enter(SeekJob aPendingSeek)
 
   MOZ_ASSERT(!mMaster->mVideoDecodeSuspended);
 
-  mPendingSeek = Move(aPendingSeek);
-
   // Dispatch tasks to decode first frames.
   mMaster->DispatchDecodeTasksIfNeeded();
 }
 
-RefPtr<MediaDecoder::SeekPromise>
-MediaDecoderStateMachine::
-DecodingFirstFrameState::HandleSeek(SeekTarget aTarget)
-{
-  // Should've transitioned to DECODING in Enter()
-  // if mSentFirstFrameLoadedEvent is true.
-  MOZ_ASSERT(!mMaster->mSentFirstFrameLoadedEvent);
-
-  if (!Reader()->ForceZeroStartTime()) {
-    SLOG("Not Enough Data to seek at this stage, queuing seek");
-    mPendingSeek.RejectIfExists(__func__);
-    mPendingSeek.mTarget = aTarget;
-    return mPendingSeek.mPromise.Ensure(__func__);
-  }
-
-  // Since ForceZeroStartTime() is true, we should've transitioned to SEEKING
-  // in Enter() if there is any pending seek.
-  MOZ_ASSERT(!mPendingSeek.Exists());
-
-  return StateObject::HandleSeek(aTarget);
-}
-
 void
 MediaDecoderStateMachine::
 DecodingFirstFrameState::MaybeFinishDecodeFirstFrame()
@@ -1365,12 +1328,7 @@ DecodingFirstFrameState::MaybeFinishDecodeFirstFrame()
   }
 
   mMaster->FinishDecodeFirstFrame();
-
-  if (mPendingSeek.Exists()) {
-    SetState<SeekingState>(Move(mPendingSeek), EventVisibility::Observable);
-  } else {
-    SetState<DecodingState>();
-  }
+  SetState<DecodingState>();
 }
 
 void