Record GCM received data message intervals in UMA

components/gcm_driver/gcm_stats_recorder_impl.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_GCM_DRIVER_GCM_STATS_RECORDER_IMPL_H_
 #define COMPONENTS_GCM_DRIVER_GCM_STATS_RECORDER_IMPL_H_
 
 #include <deque>
 #include <string>
 #include <vector>
@@ skipping 129 matching lines @@
 
   bool is_recording_;
   Delegate* delegate_;
 
   std::deque<CheckinActivity> checkin_activities_;
   std::deque<ConnectionActivity> connection_activities_;
   std::deque<RegistrationActivity> registration_activities_;
   std::deque<ReceivingActivity> receiving_activities_;
   std::deque<SendingActivity> sending_activities_;
 
+  base::Time last_received_data_message_burst_start_time_;
+
   DISALLOW_COPY_AND_ASSIGN(GCMStatsRecorderImpl);
 };
 
 }  // namespace gcm
 
 #endif  // COMPONENTS_GCM_DRIVER_GCM_STATS_RECORDER_IMPL_H_