[Chromecast] Add LogicalPause/Resume to CmaBackend

This avoid casting CmaBackend insteaces in MediaPipelineBackendManager,
which is unsafe since we don't know the real type.

Change-Id: I82ae529384575f2db5002ab1417de4a056eb3186
Reviewed-on: https://chromium-review.googlesource.com/1159221Reviewed-by: Kenneth MacKay <kmackay@chromium.org>
Reviewed-by: Sergey Volk <servolk@chromium.org>
Commit-Queue: Kenneth MacKay <kmackay@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579938}

chromecast/media/audio/cast_audio_output_stream_unittest.cc

@@ -195,6 +195,9 @@ class FakeCmaBackend : public CmaBackend {
   int64_t GetCurrentPts() override { return 0; }
   bool SetPlaybackRate(float rate) override { return true; }
 
+  void LogicalPause() override {}
+  void LogicalResume() override {}
+
   State state() const { return state_; }
   FakeAudioDecoder* decoder() const { return audio_decoder_.get(); }
 

chromecast/media/cma/backend/cma_backend.h

@@ -90,6 +90,12 @@ class CmaBackend {
   virtual bool Resume() = 0;
   virtual int64_t GetCurrentPts() = 0;
   virtual bool SetPlaybackRate(float rate) = 0;
+
+  // Logically pauses/resumes a backend instance, without actually pausing or
+  // resuming it. This is used by multiroom output to avoid playback stutter on
+  // resume.
+  virtual void LogicalPause() = 0;
+  virtual void LogicalResume() = 0;
 };
 
 }  // namespace media

chromecast/media/cma/backend/media_pipeline_backend_manager.cc

@@ -149,18 +149,6 @@ void MediaPipelineBackendManager::RemoveAllowVolumeFeedbackObserver(
   allow_volume_feedback_observers_->RemoveObserver(observer);
 }
 
-void MediaPipelineBackendManager::LogicalPause(CmaBackend* backend) {
-  MediaPipelineBackendWrapper* wrapper =
-      static_cast<MediaPipelineBackendWrapper*>(backend);
-  wrapper->LogicalPause();
-}
-
-void MediaPipelineBackendManager::LogicalResume(CmaBackend* backend) {
-  MediaPipelineBackendWrapper* wrapper =
-      static_cast<MediaPipelineBackendWrapper*>(backend);
-  wrapper->LogicalResume();
-}
-
 void MediaPipelineBackendManager::AddExtraPlayingStream(bool sfx) {
   UpdatePlayingAudioCount(sfx, 1);
 }

chromecast/media/cma/backend/media_pipeline_backend_manager.h

@@ -99,13 +99,6 @@ class MediaPipelineBackendManager {
   void AddAllowVolumeFeedbackObserver(AllowVolumeFeedbackObserver* observer);
   void RemoveAllowVolumeFeedbackObserver(AllowVolumeFeedbackObserver* observer);
 
-  // Logically pauses/resumes a backend instance, without actually pausing or
-  // resuming it. This is used by multiroom output to avoid playback stutter on
-  // resume. |backend| must have been created via a call to this instance's
-  // CreateCmaBackend().
-  void LogicalPause(CmaBackend* backend);
-  void LogicalResume(CmaBackend* backend);
-
   // Add/remove a playing audio stream that is not accounted for by a
   // CmaBackend instance (for example, direct audio output using
   // CastMediaShlib::AddDirectAudioSource()). |sfx| indicates whether or not

chromecast/media/cma/backend/media_pipeline_backend_wrapper.h

@@ -30,9 +30,6 @@ class MediaPipelineBackendWrapper : public CmaBackend {
                               MediaPipelineBackendManager* backend_manager);
   ~MediaPipelineBackendWrapper() override;
 
-  void LogicalPause();
-  void LogicalResume();
-
   // CmaBackend implementation:
   AudioDecoder* CreateAudioDecoder() override;
   VideoDecoder* CreateVideoDecoder() override;
@@ -43,6 +40,8 @@ class MediaPipelineBackendWrapper : public CmaBackend {
   bool Resume() override;
   int64_t GetCurrentPts() override;
   bool SetPlaybackRate(float rate) override;
+  void LogicalPause() override;
+  void LogicalResume() override;
 
  private:
   void SetPlaying(bool playing);

chromecast/media/cma/test/mock_cma_backend.h

@@ -64,6 +64,8 @@ class MockCmaBackend : public CmaBackend {
   MOCK_METHOD0(Resume, bool());
   MOCK_METHOD0(GetCurrentPts, int64_t());
   MOCK_METHOD1(SetPlaybackRate, bool(float));
+  MOCK_METHOD0(LogicalPause, void());
+  MOCK_METHOD0(LogicalResume, void());
 };
 
 }  // namespace media