Enforce marking "override" for functions overriding Blink.

content/renderer/wake_lock/wake_lock_dispatcher.h

 // Copyright 2015 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 CONTENT_RENDERER_WAKE_LOCK_WAKE_LOCK_DISPATCHER_H_
 #define CONTENT_RENDERER_WAKE_LOCK_WAKE_LOCK_DISPATCHER_H_
 
 #include "content/common/wake_lock_service.mojom.h"
 #include "content/public/renderer/render_frame_observer.h"
 #include "third_party/WebKit/public/platform/modules/wake_lock/WebWakeLockClient.h"
 
 namespace content {
 
 // WakeLockDispatcher sends wake lock messages to the browser process using the
 // Mojo WakeLockService.
 class WakeLockDispatcher : public RenderFrameObserver,
                            public blink::WebWakeLockClient {
  public:
   explicit WakeLockDispatcher(RenderFrame* render_frame);
   ~WakeLockDispatcher() override;
 
  private:
   // WebWakeLockClient implementation.
-  virtual void requestKeepScreenAwake(bool keepScreenAwake);
+  void requestKeepScreenAwake(bool keepScreenAwake) override;
 
   WakeLockServicePtr wake_lock_service_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_WAKE_LOCK_WAKE_LOCK_DISPATCHER_H_