[chromecast] Pass media task runner to MediaPipelineBackendManager.

chromecast/media/cma/backend/media_pipeline_backend_wrapper.h

Index: chromecast/media/cma/backend/media_pipeline_backend_wrapper.h
diff --git a/chromecast/media/cma/backend/media_pipeline_backend_wrapper.h b/chromecast/media/cma/backend/media_pipeline_backend_wrapper.h
index f2befb8a930d052c01ba4dfd64a35d72f6d826d5..f7a5c06290f3a18f4b63a9111ff72a4d2b117e7e 100644
--- a/chromecast/media/cma/backend/media_pipeline_backend_wrapper.h
+++ b/chromecast/media/cma/backend/media_pipeline_backend_wrapper.h
@@ -22,11 +22,14 @@ class SingleThreadTaskRunner;
 namespace chromecast {
 namespace media {
 
+class MediaPipelineBackendManager;
+
 class MediaPipelineBackendWrapper : public MediaPipelineBackend {
  public:
-  MediaPipelineBackendWrapper(MediaPipelineBackend* backend,
+  MediaPipelineBackendWrapper(scoped_ptr<MediaPipelineBackend> backend,
                               int stream_type,
-                              float stream_type_volume);
+                              float stream_type_volume,
+                              MediaPipelineBackendManager* backend_manager);
   ~MediaPipelineBackendWrapper() override;
 
   // MediaPipelineBackend implementation:
@@ -49,6 +52,7 @@ class MediaPipelineBackendWrapper : public MediaPipelineBackend {
   scoped_ptr<AudioDecoderWrapper> audio_decoder_wrapper_;
   float stream_type_volume_;
   bool is_initialized_;
+  MediaPipelineBackendManager* const backend_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaPipelineBackendWrapper);
 };