Add audio signal to the ResourceScheduler.

content/browser/renderer_host/media/audio_renderer_host.h

Index: content/browser/renderer_host/media/audio_renderer_host.h
diff --git a/content/browser/renderer_host/media/audio_renderer_host.h b/content/browser/renderer_host/media/audio_renderer_host.h
index f4be17f1f2cc8bef9f6a657e8644fb8f9117a811..8959cdddcbc374e41c6566a78e28dd6ee89774ae 100644
--- a/content/browser/renderer_host/media/audio_renderer_host.h
+++ b/content/browser/renderer_host/media/audio_renderer_host.h
@@ -89,6 +89,10 @@ class CONTENT_EXPORT AudioRendererHost : public BrowserMessageFilter {
   // be called from any thread.
   bool HasActiveAudio();
 
+  // Returns true if any streams managed by the RenderView identified by
+  // |render_view_id| are actively playing. Can be called from any thread.
+  bool RenderViewHasActiveAudio(int render_view_id) const;
+
  private:
   friend class AudioRendererHostTest;
   friend class BrowserThread;
@@ -157,6 +161,10 @@ class CONTENT_EXPORT AudioRendererHost : public BrowserMessageFilter {
   // Returns NULL if not found.
   AudioEntry* LookupById(int stream_id);
 
+  // A helper method to update the number of playing streams and alert the
+  // ResourceScheduler when the renderer starts or stops playing an audiostream.
+  void UpdateNumPlayingStreams(AudioEntry* entry, bool is_playing);
+
   // ID of the RenderProcessHost that owns this instance.
   const int render_process_id_;