Fix start/stop of html5 audio stream and race condition when pausing.

content/renderer/renderer_webaudiodevice_impl.h

 // Copyright (c) 2011 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_RENDERER_WEBAUDIODEVICE_IMPL_H_
 #define CONTENT_RENDERER_RENDERER_WEBAUDIODEVICE_IMPL_H_
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "content/renderer/media/audio_device.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebAudioDevice.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebVector.h"
 
 class RendererWebAudioDeviceImpl : public WebKit::WebAudioDevice,
                                    public AudioDevice::RenderCallback {
  public:
   RendererWebAudioDeviceImpl(size_t buffer_size,
                              int channels,
                              double sample_rate,
                              WebKit::WebAudioDevice::RenderCallback* callback);
   virtual ~RendererWebAudioDeviceImpl();
 
   // WebKit::WebAudioDevice implementation.
   virtual void start();
   virtual void stop();
   virtual double sampleRate();
 
   // AudioDevice::RenderCallback implementation.
-  virtual void Render(const std::vector<float*>& audio_data,
-                      size_t number_of_frames,
-                      size_t audio_delay_milliseconds) OVERRIDE;
+  virtual size_t Render(const std::vector<float*>& audio_data,
+                        size_t number_of_frames,
+                        size_t audio_delay_milliseconds) OVERRIDE;
 
  private:
   scoped_refptr<AudioDevice> audio_device_;
   bool is_running_;
 
   // Weak reference to the callback into WebKit code.
   WebKit::WebAudioDevice::RenderCallback* client_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererWebAudioDeviceImpl);
 };
 
 #endif  // CONTENT_RENDERER_RENDERER_WEBAUDIODEVICE_IMPL_H_