Standardize usage of virtual/override/final in content/browser/

content/browser/power_save_blocker_impl.h

 // Copyright (c) 2013 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_BROWSER_POWER_SAVE_BLOCKER_IMPL_H_
 #define CONTENT_BROWSER_POWER_SAVE_BLOCKER_IMPL_H_
 
 #include "base/memory/ref_counted.h"
 #include "content/public/browser/power_save_blocker.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace content {
 
 class PowerSaveBlockerImpl : public PowerSaveBlocker {
  public:
   PowerSaveBlockerImpl(PowerSaveBlockerType type, const std::string& reason);
-  virtual ~PowerSaveBlockerImpl();
+  ~PowerSaveBlockerImpl() override;
 
 #if defined(OS_ANDROID)
   // In Android platform, the kPowerSaveBlockPreventDisplaySleep type of
   // PowerSaveBlocker should associated with the ViewAndroid,
   // so the blocker could be removed by platform if the view isn't visble
   void InitDisplaySleepBlocker(gfx::NativeView view_android);
 #endif
 
  private:
   class Delegate;
 
   // Implementations of this class may need a second object with different
   // lifetime than the RAII container, or additional storage. This member is
   // here for that purpose. If not used, just define the class as an empty
   // RefCounted (or RefCountedThreadSafe) like so to make it compile:
   // class PowerSaveBlocker::Delegate
   //     : public base::RefCounted<PowerSaveBlocker::Delegate> {
   //  private:
   //   friend class base::RefCounted<Delegate>;
   //   ~Delegate() {}
   // };
   scoped_refptr<Delegate> delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(PowerSaveBlockerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_POWER_SAVE_BLOCKER_IMPL_H_