Standardize usage of virtual/override/final in mojo/

mojo/shell/shell_test_base_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 "mojo/shell/shell_test_base.h"
 
 #include "base/bind.h"
 #include "base/i18n/time_formatting.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 56 matching lines @@
   void SetAndQuitImpl(T* val, T result) {
     *val = result;
     message_loop()->QuitWhenIdle();
   }
   TestTrackedRequestServicePtr request_tracking_;
 };
 
 class QuitMessageLoopErrorHandler : public ErrorHandler {
  public:
   QuitMessageLoopErrorHandler() {}
-  virtual ~QuitMessageLoopErrorHandler() {}
+  ~QuitMessageLoopErrorHandler() override {}
 
   // |ErrorHandler| implementation:
-  virtual void OnConnectionError() override {
+  void OnConnectionError() override {
     base::MessageLoop::current()->QuitWhenIdle();
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(QuitMessageLoopErrorHandler);
 };
 
 // Tests that we can connect to a single service within a single app.
 TEST_F(ShellTestBaseTest, ConnectBasic) {
   InterfacePtr<TestService> service;
@@ skipping 208 matching lines @@
   EXPECT_EQ(TestTimeService::Name_, reports[1].service_name);
   EXPECT_EQ(1U, reports[1].total_requests);
   EXPECT_EQ(TestTimeService::Name_, reports[2].service_name);
   EXPECT_EQ(20U, reports[2].total_requests);
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace shell
 }  // namespace mojo