Fix webrtcAudioPrivate API to handle requests from <webview>s.

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 7be2c60a02c743111bf8a2e8df0095e1138c2f17..23d1c6101c8a2c85f32b4d112ede935c39459cd9 100644
--- a/content/browser/renderer_host/render_process_host_impl.h
+++ b/content/browser/renderer_host/render_process_host_impl.h
@@ -270,6 +270,9 @@ class CONTENT_EXPORT RenderProcessHostImpl
   // immediately after receiving response headers.
   void ResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
 
+  void GetAudioOutputControllers(
+      const GetAudioOutputControllersCallback& callback) const override;
+
  protected:
   // A proxy for our IPC::Channel that lives on the IO thread (see
   // browser_process.h)