Enable renderer side mixing behind a flag.

content/renderer/render_thread_impl.h

 // 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.
 
 #ifndef CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 #define CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 35 matching lines @@
 
 namespace base {
 class MessageLoopProxy;
 class Thread;
 namespace win {
 class ScopedCOMInitializer;
 }
 }
 
 namespace content {
+class AudioRendererMixerManager;
 class BrowserPluginChannelManager;
 class BrowserPluginRegistry;
 class MediaStreamCenter;
 class RenderProcessObserver;
 }
 
 namespace v8 {
 class Extension;
 }
 
@@ skipping 150 matching lines @@
   // not sent for at least one notification delay.
   void PostponeIdleNotification();
 
   // Returns a graphics context shared among all
   // RendererGpuVideoDecoderFactories, or NULL on error.  Context remains owned
   // by this class and must be null-tested before each use to detect context
   // loss.  The returned WeakPtr<> is only valid on the compositor thread when
   // threaded compositing is enabled.
   base::WeakPtr<WebGraphicsContext3DCommandBufferImpl> GetGpuVDAContext3D();
 
+  content::AudioRendererMixerManager* audio_renderer_mixer_manager() {
+    return audio_renderer_mixer_manager_.get();
+  }
+
  private:
   virtual bool OnControlMessageReceived(const IPC::Message& msg) OVERRIDE;
 
   void Init();
 
   void OnSetZoomLevelForCurrentURL(const std::string& host, double zoom_level);
   void OnSetCSSColors(const std::vector<CSSColors::CSSColorMapping>& colors);
   void OnCreateNewView(const ViewMsg_New_Params& params);
   void OnTransferBitmap(const SkBitmap& bitmap, int resource_id);
   void OnPurgePluginListCache(bool reload_pages);
@@ skipping 60 matching lines @@
   std::set<std::string> v8_extensions_;
 
   bool compositor_initialized_;
   scoped_ptr<CompositorThread> compositor_thread_;
   scoped_ptr<content::BrowserPluginRegistry> browser_plugin_registry_;
 
   ObserverList<content::RenderProcessObserver> observers_;
 
   scoped_ptr<WebGraphicsContext3DCommandBufferImpl> gpu_vda_context3d_;
 
+  // AudioRendererMixerManager instance which manages renderer side mixer
+  // instances shared based on configured audio parameters.
+  scoped_ptr<content::AudioRendererMixerManager> audio_renderer_mixer_manager_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };
 
 #endif  // CONTENT_RENDERER_RENDER_THREAD_IMPL_H_