Add polling and audio check to copresence.

components/copresence/public/copresence_delegate.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_DELEGATE_H_
 #define COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_DELEGATE_H_
 
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 
 namespace net {
 class URLRequestContextGetter;
 }
 
 namespace copresence {
 
 class Message;
 class WhispernetClient;
 
-enum CopresenceStatus { SUCCESS, FAIL };
+// AUDIO_FAIL indicates that we weren't able to hear the audio token that
+// we were playing.
+enum CopresenceStatus { SUCCESS, FAIL, AUDIO_FAIL };
 
 // Callback type to send a status.
 typedef base::Callback<void(CopresenceStatus)> StatusCallback;
 
 // A delegate interface for users of Copresence.
 class CopresenceDelegate {
  public:
   virtual ~CopresenceDelegate() {}
 
   // This method will be called when we have subscribed messages
   // that need to be sent to their respective apps.
   virtual void HandleMessages(
       const std::string& app_id,
       const std::string& subscription_id,
       const std::vector<Message>& message) = 0;
 
+  virtual void HandleStatusUpdate(CopresenceStatus status) = 0;
+
   // Thw URLRequestContextGetter must outlive the CopresenceManager.
   virtual net::URLRequestContextGetter* GetRequestContext() const = 0;
 
   virtual const std::string GetPlatformVersionString() const = 0;
 
   virtual const std::string GetAPIKey(const std::string& app_id) const = 0;
   virtual const std::string GetAuthToken() const = 0;
 
   // Thw WhispernetClient must outlive the CopresenceManager.
   virtual WhispernetClient* GetWhispernetClient() = 0;
 };
 
 }  // namespace copresence
 
 #endif  // COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_DELEGATE_H_