Standardize usage of virtual/override/final specifiers.

components/gcm_driver/gcm_account_mapper_unittest.cc

 // 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.
 
 #include "components/gcm_driver/gcm_account_mapper.h"
 
 #include "base/test/simple_test_clock.h"
 #include "base/time/time.h"
 #include "components/gcm_driver/fake_gcm_driver.h"
 #include "google_apis/gcm/engine/account_mapping.h"
@@ skipping 221 matching lines @@
   last_action_ = action;
   last_message_id_ = message_id;
   all_messages_[message_id] = action;
 }
 
 }  // namespace
 
 class GCMAccountMapperTest : public testing::Test {
  public:
   GCMAccountMapperTest();
-  virtual ~GCMAccountMapperTest();
+  ~GCMAccountMapperTest() override;
 
   void Restart();
 
   const GCMAccountMapper::AccountMappings& GetAccounts() const {
     return account_mapper_->accounts_;
   }
 
   GCMAccountMapper* mapper() { return account_mapper_.get(); }
 
   CustomFakeGCMDriver& gcm_driver() { return gcm_driver_; }
@@ skipping 651 matching lines @@
   expected_mappings[1].status_change_timestamp = clock()->Now();
   expected_mappings[1].status = AccountMapping::MAPPED;
   expected_mappings[2].status_change_timestamp = clock()->Now();
   expected_mappings[2].status = AccountMapping::MAPPED;
 
   VerifyMappings(
       expected_mappings, GetAccounts(), "Step 6, Three mapped accounts");
 }
 
 }  // namespace gcm