Strip out stream counting from AudioRendererHost.

content/browser/renderer_host/render_process_host_impl.h

Index: content/browser/renderer_host/render_process_host_impl.h
diff --git a/content/browser/renderer_host/render_process_host_impl.h b/content/browser/renderer_host/render_process_host_impl.h
index dc269f22f81e0de9e99767e95c6d651588c93ff4..f0ad8aef98f447a2d10c0a54ed4b6ae9fe63f13a 100644
--- a/content/browser/renderer_host/render_process_host_impl.h
+++ b/content/browser/renderer_host/render_process_host_impl.h
@@ -123,7 +123,6 @@ class CONTENT_EXPORT RenderProcessHostImpl
   void WidgetRestored() override;
   void WidgetHidden() override;
   int VisibleWidgetCount() const override;
-  void AudioStateChanged() override;
   bool IsForGuestsOnly() const override;
   StoragePartition* GetStoragePartition() const override;
   bool Shutdown(int exit_code, bool wait) override;
@@ -287,6 +286,12 @@ class CONTENT_EXPORT RenderProcessHostImpl
 
   void RecomputeAndUpdateWebKitPreferences();
 
+  // Called when an audio stream is added or removed and used to determine if
+  // the process should be backgrounded or not.
+  void OnAudioStreamAdded() override;
+  void OnAudioStreamRemoved() override;
+  int get_audio_stream_count_for_testing() const { return audio_stream_count_; }
+
  protected:
   // A proxy for our IPC::Channel that lives on the IO thread.
   std::unique_ptr<IPC::ChannelProxy> channel_;
@@ -599,6 +604,10 @@ class CONTENT_EXPORT RenderProcessHostImpl
   mojom::RouteProviderAssociatedPtr remote_route_provider_;
   mojom::RendererAssociatedPtr renderer_interface_;
 
+  // Tracks active audio streams within the render process; used to determine if
+  // if a process should be backgrounded.
+  int audio_stream_count_ = 0;
+
   // A WeakPtrFactory which is reset every time Cleanup() runs. Used to vend
   // WeakPtrs which are invalidated any time the RPHI is recycled.
   std::unique_ptr<base::WeakPtrFactory<RenderProcessHostImpl>>