Have FakeGCMProfileService return different registration IDs each time

chrome/browser/services/gcm/fake_gcm_profile_service.h

 // Copyright 2013 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 CHROME_BROWSER_SERVICES_GCM_FAKE_GCM_PROFILE_SERVICE_H_
 #define CHROME_BROWSER_SERVICES_GCM_FAKE_GCM_PROFILE_SERVICE_H_
 
 #include <list>
 #include <vector>
 
@@ skipping 46 matching lines @@
   }
 
   void set_collect(bool collect) {
     collect_ = collect;
   }
 
  private:
   // Indicates whether the service will collect paramters of the calls for
   // furter verification in tests.
   bool collect_;
+  // Used to give each registration a unique registration id. Does not decrease
+  // when unregister is called.
+  int registration_count_;
   std::string last_registered_app_id_;
   std::vector<std::string> last_registered_sender_ids_;
   std::list<GCMClient::Result> unregister_responses_;
   GCMClient::OutgoingMessage last_sent_message_;
   std::string last_receiver_id_;
   UnregisterCallback unregister_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeGCMProfileService);
 };
 
 }  // namespace gcm
 
 #endif  // CHROME_BROWSER_SERVICES_GCM_FAKE_GCM_PROFILE_SERVICE_H_