Standardize usage of virtual/override/final in components/

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>
 
 #include "base/time/time.h"
 
 namespace gcm {
 
 // Contains data that are common to all activity kinds below.
 struct Activity {
   Activity();
   virtual ~Activity();
 
   base::Time time;
   std::string event;    // A short description of the event.
   std::string details;  // Any additional detail about the event.
 };
 
 // Contains relevant data of a connection activity.
 struct ConnectionActivity : Activity {
   ConnectionActivity();
-  virtual ~ConnectionActivity();
+  ~ConnectionActivity() override;
 };
 
 // Contains relevant data of a check-in activity.
 struct CheckinActivity : Activity {
   CheckinActivity();
-  virtual ~CheckinActivity();
+  ~CheckinActivity() override;
 };
 
 // Contains relevant data of a registration/unregistration step.
 struct RegistrationActivity : Activity {
   RegistrationActivity();
-  virtual ~RegistrationActivity();
+  ~RegistrationActivity() override;
 
   std::string app_id;
   std::string sender_ids;  // Comma separated sender ids.
 };
 
 // Contains relevant data of a message receiving event.
 struct ReceivingActivity : Activity {
   ReceivingActivity();
-  virtual ~ReceivingActivity();
+  ~ReceivingActivity() override;
 
   std::string app_id;
   std::string from;
   int message_byte_size;
 };
 
 // Contains relevant data of a send-message step.
 struct SendingActivity : Activity {
   SendingActivity();
-  virtual ~SendingActivity();
+  ~SendingActivity() override;
 
   std::string app_id;
   std::string receiver_id;
   std::string message_id;
 };
 
 struct RecordedActivities {
   RecordedActivities();
   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;
 };
 
 }  // namespace gcm
 
 #endif  // COMPONENTS_GCM_DRIVER_GCM_ACTIVITY_H_