Adding an interface to allow extention of the audio player for CRD and iOS.

remoting/client/plugin/chromoting_instance.h

Index: remoting/client/plugin/chromoting_instance.h
diff --git a/remoting/client/plugin/chromoting_instance.h b/remoting/client/plugin/chromoting_instance.h
index 38ad319bd49e68fd46a7d5136504c4bacb511aa1..ebe702471e1d3a7d148eba3e8aaf4d7c43cbfb8c 100644
--- a/remoting/client/plugin/chromoting_instance.h
+++ b/remoting/client/plugin/chromoting_instance.h
@@ -60,6 +60,7 @@ class DesktopVector;
 
 namespace remoting {
 
+class PepperAudioPlayer;
 class ChromotingClient;
 class ClientContext;
 class DelegatingSignalStrategy;
@@ -248,6 +249,7 @@ class ChromotingInstance : public ClientUserInterface,
   std::unique_ptr<jingle_glue::JingleThreadWrapper> thread_wrapper_;
   ClientContext context_;
   protocol::PerformanceTracker perf_tracker_;
+  std::unique_prt<PepperAudioPlayer> audio_player_;
   std::unique_ptr<PepperVideoRenderer> video_renderer_;
   pp::View plugin_view_;