Make AudioPlayer optional in ChromotingClient

remoting/client/chromoting_client.h

Index: remoting/client/chromoting_client.h
diff --git a/remoting/client/chromoting_client.h b/remoting/client/chromoting_client.h
index 3ccde00cbec68554d7af4480904618eea5f73dec..0facafa5d2875b303ca35d93f7665ba308de9b36 100644
--- a/remoting/client/chromoting_client.h
+++ b/remoting/client/chromoting_client.h
@@ -42,6 +42,7 @@ class SignalStrategy;
 class ChromotingClient : public protocol::ConnectionToHost::HostEventCallback,
                          public protocol::ClientStub {
  public:
+  // A null pointer in |audio_player| disables the audio stream.

[Wez, 2013/07/09 20:08:07]

nit: We should have a comment here that clarifies the ClientContext etc object
lifetime requirements... for this CL, though, I'd suggest "|audio_player| may be
null, in which case audio will not be requested."

[solb, 2013/07/10 00:00:31]

Done.

   ChromotingClient(const ClientConfig& config,
                    ClientContext* client_context,
                    protocol::ConnectionToHost* connection,