Move passing of WebRTC rendering frames to IO thread

content/shell/renderer/layout_test/test_media_stream_video_renderer.cc

 // Copyright 2013 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/shell/renderer/layout_test/test_media_stream_video_renderer.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "media/base/video_frame.h"
 
 namespace content {
 
 TestMediaStreamVideoRenderer::TestMediaStreamVideoRenderer(
+    const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner,
     const gfx::Size& size,
     const base::TimeDelta& frame_duration,
     const base::Closure& error_cb,
     const MediaStreamVideoRenderer::RepaintCB& repaint_cb)
     : task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      io_task_runner_(io_task_runner),
       size_(size),
       state_(kStopped),
       frame_duration_(frame_duration),
       error_cb_(error_cb),
-      repaint_cb_(repaint_cb) {
-}
+      repaint_cb_(repaint_cb) {}
 
 TestMediaStreamVideoRenderer::~TestMediaStreamVideoRenderer() {}
 
 void TestMediaStreamVideoRenderer::Start() {
   DVLOG(1) << "TestMediaStreamVideoRenderer::Start";
   DCHECK(task_runner_->BelongsToCurrentThread());
   state_ = kStarted;
   task_runner_->PostTask(
       FROM_HERE, base::Bind(&TestMediaStreamVideoRenderer::GenerateFrame,
                             this));
@@ skipping 26 matching lines @@
     return;
 
   if (state_ == kStarted) {
     // Always allocate a new frame filled with white color.
     scoped_refptr<media::VideoFrame> video_frame =
         media::VideoFrame::CreateColorFrame(
             size_, 255, 128, 128, current_time_);
 
     // TODO(wjia): set pixel data to pre-defined patterns if it's desired to
     // verify frame content.
-
-    repaint_cb_.Run(video_frame);
+    io_task_runner_->PostTask(FROM_HERE, base::Bind(repaint_cb_, video_frame));
   }
 
   current_time_ += frame_duration_;
   task_runner_->PostDelayedTask(
       FROM_HERE, base::Bind(&TestMediaStreamVideoRenderer::GenerateFrame, this),
       frame_duration_);
 }
 
 }  // namespace content