components: Add out-of-line copy ctors for complex classes.

components/gcm_driver/gcm_activity.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_ACTIVITY_H_
 #define COMPONENTS_GCM_DRIVER_GCM_ACTIVITY_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 56 matching lines @@
 // Contains relevant data of a message decryption failure.
 struct DecryptionFailureActivity : Activity {
   DecryptionFailureActivity();
   ~DecryptionFailureActivity() override;
 
   std::string app_id;
 };
 
 struct RecordedActivities {
   RecordedActivities();
+  RecordedActivities(const RecordedActivities& other);
   virtual ~RecordedActivities();
 
   std::vector<CheckinActivity> checkin_activities;
   std::vector<ConnectionActivity> connection_activities;
   std::vector<RegistrationActivity> registration_activities;
   std::vector<ReceivingActivity> receiving_activities;
   std::vector<SendingActivity> sending_activities;
   std::vector<DecryptionFailureActivity> decryption_failure_activities;
 };
 
 }  // namespace gcm
 
 #endif  // COMPONENTS_GCM_DRIVER_GCM_ACTIVITY_H_