Move passing of WebRTC rendering frames from main thread to compositor thread

content/renderer/media/webmediaplayer_ms_compositor.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_MEDIA_WEBMEDIAPLAYER_MS_COMPOSITOR_H_
 #define CONTENT_RENDERER_MEDIA_WEBMEDIAPLAYER_MS_COMPOSITOR_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 70 matching lines @@
   // Difference between GetCurrentFrame(): GetCurrentFrame() is designed for
   // chrome compositor to pull frame from WebMediaPlayerMSCompositor, and thus
   // calling GetCurrentFrame() will affect statistics like |dropped_frames_|
   // etc. Calling this function has no side effect.
   scoped_refptr<media::VideoFrame> GetCurrentFrameWithoutUpdatingStatistics();
 
   void StartRendering();
   void StopRendering();
   void ReplaceCurrentFrameWithACopy();
 
+  base::WeakPtr<WebMediaPlayerMSCompositor> GetWeakPtr();

[perkj_chrome, 2016/11/09 15:27:13]

So these weakptr's may only be dereferences on the compositor? That is not
obvious from just looking at the header file.  Does it have to be public? 

[emircan, 2016/11/11 22:27:19]

Yes, they would be used to post tasks on compositor thread and invalidated on
compositor thread via ~WebMediaPlayerMSCompositor. 

It needs to be public because WebMediaPlayerMS needs to access it.

+
  private:
   friend class WebMediaPlayerMSTest;
 
   bool MapTimestampsToRenderTimeTicks(
       const std::vector<base::TimeDelta>& timestamps,
       std::vector<base::TimeTicks>* wall_clock_times);
 
   void SetCurrentFrame(const scoped_refptr<media::VideoFrame>& frame);
 
   // For algorithm enabled case only: given the render interval, update
@@ skipping 48 matching lines @@
 
   bool stopped_;
 
   std::map<base::TimeDelta, base::TimeTicks> timestamps_to_clock_times_;
 
   // |current_frame_lock_| protects |current_frame_used_by_compositor_|,
   // |current_frame_|, and |rendering_frame_buffer_|.
   base::Lock current_frame_lock_;
 
   // Make sure the weak pointer factory member is the last member of the class.
-  base::WeakPtrFactory<WebMediaPlayerMSCompositor> weak_ptr_factory_;
+  base::WeakPtrFactory<WebMediaPlayerMSCompositor> weak_factory_for_compositor_;
 
   DISALLOW_COPY_AND_ASSIGN(WebMediaPlayerMSCompositor);
 };
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBMEDIAPLAYER_MS_COMPOSITOR_H_