Cast: deliver video frames on the IO thread

content/renderer/media/mock_media_stream_video_sink.cc

 // Copyright 2014 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/mock_media_stream_video_sink.h"
 
+#include "media/base/bind_to_current_loop.h"
+
 namespace content {
 
 MockMediaStreamVideoSink::MockMediaStreamVideoSink()
     : number_of_frames_(0),
       enabled_(true),
       format_(media::VideoFrame::UNKNOWN),
-      state_(blink::WebMediaStreamSource::ReadyStateLive) {
+      state_(blink::WebMediaStreamSource::ReadyStateLive),
+      weak_factory_(this) {

[perkj_chrome, 2014/05/08 08:15:08]

Can you add thread checks to this class? Just to make it obvious that all still
happen on the main render thread.

 }
 
 MockMediaStreamVideoSink::~MockMediaStreamVideoSink() {
 }
 
-void MockMediaStreamVideoSink::OnVideoFrame(
-    const scoped_refptr<media::VideoFrame>& frame) {
+VideoCaptureDeliverFrameCB
+MockMediaStreamVideoSink::GetDeliverFrameCB() {
+  return media::BindToCurrentLoop(
+      base::Bind(
+          &MockMediaStreamVideoSink::DeliverVideoFrame,
+          weak_factory_.GetWeakPtr()));
+}
+
+void MockMediaStreamVideoSink::DeliverVideoFrame(
+    const scoped_refptr<media::VideoFrame>& frame,
+    const media::VideoCaptureFormat& format) {
   ++number_of_frames_;
   format_ = frame->format();
   frame_size_ = frame->natural_size();
   OnVideoFrame();
 }
 
 void MockMediaStreamVideoSink::OnReadyStateChanged(
     blink::WebMediaStreamSource::ReadyState state) {
   state_ = state;
 }
 
 void MockMediaStreamVideoSink::OnEnabledChanged(bool enabled) {
   enabled_ = enabled;
 }
 
 }  // namespace content