Add audio signal to the ResourceScheduler.

content/browser/loader/resource_dispatcher_host_impl.h

Index: content/browser/loader/resource_dispatcher_host_impl.h
diff --git a/content/browser/loader/resource_dispatcher_host_impl.h b/content/browser/loader/resource_dispatcher_host_impl.h
index 48d975520e28b9e28efb987dfe47bf9519c6f080..c0483dcf6ea56a4e332d1a3f492a2e2affdf858e 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.h
+++ b/content/browser/loader/resource_dispatcher_host_impl.h
@@ -180,6 +180,11 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
   // Called when a RenderViewHost is shown.
   void OnRenderViewHostWasShown(int child_id, int route_id);
 
+  // Called when an AudioRenderHost starts or stops playing.
+  void OnAudioRenderHostStreamStateChanged(int child_id,
+                                           int route_id,
+                                           bool is_playing);
+
   // Force cancels any pending requests for the given process.
   void CancelRequestsForProcess(int child_id);