Add audio signal to the ResourceScheduler.

content/browser/renderer_host/render_view_host_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_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_IMPL_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 84 matching lines @@
   // which case RenderWidgetHost will create a new one.  |swapped_out| indicates
   // whether the view should initially be swapped out (e.g., for an opener
   // frame being rendered by another process). |hidden| indicates whether the
   // view is initially hidden or visible.
   //
   // The |session_storage_namespace| parameter allows multiple render views and
   // WebContentses to share the same session storage (part of the WebStorage
   // spec) space. This is useful when restoring contentses, but most callers
   // should pass in NULL which will cause a new SessionStorageNamespace to be
   // created.
-  RenderViewHostImpl(
-      SiteInstance* instance,
-      RenderViewHostDelegate* delegate,
-      RenderWidgetHostDelegate* widget_delegate,
-      int routing_id,
-      int main_frame_routing_id,
-      bool swapped_out,
-      bool hidden);
+  RenderViewHostImpl(SiteInstance* instance,
+                     RenderViewHostDelegate* delegate,
+                     RenderWidgetHostDelegate* widget_delegate,
+                     int routing_id,
+                     int main_frame_routing_id,
+                     bool swapped_out,
+                     bool hidden,
+                     bool setup_for_testing);

[jam, 2014/10/01 00:12:36]

nit: can we just call this create_audio_renderer_host and flip its meaning?
setup_for_testing is vague

   virtual ~RenderViewHostImpl();
 
   // RenderViewHost implementation.
   virtual RenderFrameHost* GetMainFrame() OVERRIDE;
   virtual void AllowBindings(int binding_flags) OVERRIDE;
   virtual void ClearFocusedElement() OVERRIDE;
   virtual bool IsFocusedElementEditable() OVERRIDE;
   virtual void ClosePage() OVERRIDE;
   virtual void CopyImageAt(int x, int y) OVERRIDE;
   virtual void SaveImageAt(int x, int y) OVERRIDE;
@@ skipping 345 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(RenderViewHostImpl);
 };
 
 #if defined(COMPILER_MSVC)
 #pragma warning(pop)
 #endif
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_IMPL_H_