Reland: Use a shared thread for media operations (round 3).

content/renderer/render_thread_impl.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/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
@@ skipping 1312 matching lines @@
 scoped_refptr<base::MessageLoopProxy>
 RenderThreadImpl::GetFileThreadMessageLoopProxy() {
   DCHECK(message_loop() == base::MessageLoop::current());
   if (!file_thread_) {
     file_thread_.reset(new base::Thread("Renderer::FILE"));
     file_thread_->Start();
   }
   return file_thread_->message_loop_proxy();
 }
 
+scoped_refptr<base::MessageLoopProxy>
+RenderThreadImpl::GetMediaThreadMessageLoopProxy() {
+  DCHECK(message_loop() == base::MessageLoop::current());
+  if (!media_thread_) {
+    media_thread_.reset(new base::Thread("Media"));
+    media_thread_->Start();
+  }
+  return media_thread_->message_loop_proxy();
+}
+
 void RenderThreadImpl::SetFlingCurveParameters(
     const std::vector<float>& new_touchpad,
     const std::vector<float>& new_touchscreen) {
   webkit_platform_support_->SetFlingCurveParameters(new_touchpad,
                                                     new_touchscreen);
 
 }
 
 }  // namespace content