Fixed the audio backgrounding bug

content/public/browser/render_process_host.h

Index: content/public/browser/render_process_host.h
diff --git a/content/public/browser/render_process_host.h b/content/public/browser/render_process_host.h
index 75a0f9e2a3e0efd149c9c00efababcbc1e9af2a1..522eb1ae0a20a264f2dab048dd88f650d2e00a33 100644
--- a/content/public/browser/render_process_host.h
+++ b/content/public/browser/render_process_host.h
@@ -99,6 +99,9 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
   virtual void WidgetHidden() = 0;
   virtual int VisibleWidgetCount() const = 0;
 
+  // Called when the audio state changes for this render process host.
+  virtual void AudioStateChanged() = 0;
+
   // Indicates whether the current RenderProcessHost is exclusively hosting
   // guest RenderFrames. Not all guest RenderFrames are created equal.  A guest,
   // as indicated by BrowserPluginGuest::IsGuest, may coexist with other
@@ -282,6 +285,11 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
   // any RenderViewHosts that are swapped out.
   int GetActiveViewCount();
 
+#if defined(OS_MACOSX)
+  // Returns the mach port associated with the process. Use only for testing.
+  virtual mach_port_t GetMachTaskPortForTesting() const = 0;
+#endif
+
   // Static management functions -----------------------------------------------
 
   // Flag to run the renderer in process.  This is primarily