Undoing revert, cl is not the cause of gcm crash on canary.

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 gcm {
+class GCMDriver;
+}
+
 namespace net {
 class URLRequestContextGetter;
 }
 
 namespace copresence {
 
 class Message;
 class WhispernetClient;
 
 // AUDIO_FAIL indicates that we weren't able to hear the audio token that
@@ skipping 19 matching lines @@
 
   // 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;
 
   // Thw WhispernetClient must outlive the CopresenceManager.
   virtual WhispernetClient* GetWhispernetClient() = 0;
+
+  // Clients may optionally provide a GCMDriver to receive messages from.
+  // If no driver is available, this can return null.
+  virtual gcm::GCMDriver* GetGCMDriver() = 0;
 };
 
 }  // namespace copresence
 
 #endif  // COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_DELEGATE_H_