Fixed the audio backgrounding bug

content/public/test/mock_render_process_host.h

Index: content/public/test/mock_render_process_host.h
diff --git a/content/public/test/mock_render_process_host.h b/content/public/test/mock_render_process_host.h
index 0b2a7e0180ff07b4424cc1f4370432c7cf249ff0..380085758f4c14cc61b14ee1ca053b7a0ec5d6ff 100644
--- a/content/public/test/mock_render_process_host.h
+++ b/content/public/test/mock_render_process_host.h
@@ -47,6 +47,7 @@ class MockRenderProcessHost : public RenderProcessHost {
   void WidgetRestored() override;
   void WidgetHidden() override;
   int VisibleWidgetCount() const override;
+  void AudioStateChanged() override;
   bool IsForGuestsOnly() const override;
   StoragePartition* GetStoragePartition() const override;
   virtual void AddWord(const base::string16& word);
@@ -95,6 +96,10 @@ class MockRenderProcessHost : public RenderProcessHost {
                                    int cdm_id) const override;
 #endif
 
+#if defined(OS_MACOSX)
+  mach_port_t GetMachTaskPortForTesting() const override;
+#endif
+
   // IPC::Sender via RenderProcessHost.
   bool Send(IPC::Message* msg) override;