Cast: deliver video frames on the IO thread

content/renderer/media/rtc_video_renderer.cc

 // Copyright (c) 2012 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.
 
 #include "content/renderer/media/rtc_video_renderer.h"
 
 #include "base/debug/trace_event.h"
 #include "base/message_loop/message_loop_proxy.h"
+#include "media/base/bind_to_current_loop.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_util.h"
 
 const int kMinFrameSize = 2;
 
 namespace content {
 
 RTCVideoRenderer::RTCVideoRenderer(
     const blink::WebMediaStreamTrack& video_track,
     const base::Closure& error_cb,
     const RepaintCB& repaint_cb)
     : error_cb_(error_cb),
       repaint_cb_(repaint_cb),
       message_loop_proxy_(base::MessageLoopProxy::current()),
       state_(STOPPED),
       frame_size_(kMinFrameSize, kMinFrameSize),
-      video_track_(video_track) {
+      video_track_(video_track),
+      weak_factory_(this) {
 }
 
 RTCVideoRenderer::~RTCVideoRenderer() {
 }
 
 void RTCVideoRenderer::Start() {
   DCHECK(message_loop_proxy_->BelongsToCurrentThread());
   DCHECK_EQ(state_, STOPPED);
 
-  AddToVideoTrack(this, video_track_);
+  AddToVideoTrack(
+      this,
+      media::BindToCurrentLoop(
+          base::Bind(
+              &RTCVideoRenderer::OnVideoFrame,
+              weak_factory_.GetWeakPtr())),
+      video_track_);
   state_ = STARTED;
 
   if (video_track_.source().readyState() ==
           blink::WebMediaStreamSource::ReadyStateEnded ||
       !video_track_.isEnabled()) {
     RenderSignalingFrame();
   }
 }
 
 void RTCVideoRenderer::Stop() {
   DCHECK(message_loop_proxy_->BelongsToCurrentThread());
   DCHECK(state_ == STARTED || state_ == PAUSED);
   RemoveFromVideoTrack(this, video_track_);
+  weak_factory_.InvalidateWeakPtrs();
   state_ = STOPPED;
   frame_size_.set_width(kMinFrameSize);
   frame_size_.set_height(kMinFrameSize);
 }
 
 void RTCVideoRenderer::Play() {
   DCHECK(message_loop_proxy_->BelongsToCurrentThread());
   if (state_ == PAUSED) {
     state_ = STARTED;
   }
@@ skipping 13 matching lines @@
     RenderSignalingFrame();
 }
 
 void RTCVideoRenderer::OnEnabledChanged(bool enabled) {
   DCHECK(message_loop_proxy_->BelongsToCurrentThread());
   if (!enabled)
     RenderSignalingFrame();
 }
 
 void RTCVideoRenderer::OnVideoFrame(
-    const scoped_refptr<media::VideoFrame>& frame) {
+    const scoped_refptr<media::VideoFrame>& frame,
+    const media::VideoCaptureFormat& format) {
   DCHECK(message_loop_proxy_->BelongsToCurrentThread());
   if (state_ != STARTED) {
     return;
   }
 
   frame_size_ = frame->natural_size();
 
   TRACE_EVENT_INSTANT1("rtc_video_renderer",
                        "OnVideoFrame",
                        TRACE_EVENT_SCOPE_THREAD,
                        "timestamp",
                        frame->timestamp().InMilliseconds());
   repaint_cb_.Run(frame);
 }
 
 void RTCVideoRenderer::RenderSignalingFrame() {
   // This is necessary to make sure audio can play if the video tag src is
   // a MediaStream video track that has been rejected, ended or disabled.
   // It also ensure that the renderer don't hold a reference to a real video
   // frame if no more frames are provided. This is since there might be a
   // finite number of available buffers. E.g, video that
   // originates from a video camera.
   scoped_refptr<media::VideoFrame> video_frame =
       media::VideoFrame::CreateBlackFrame(frame_size_);
-  OnVideoFrame(video_frame);
+  OnVideoFrame(video_frame, media::VideoCaptureFormat());
 }
 
 }  // namespace content