Fix virtual/override/final usage in Source/web/.

Source/web/NotificationPermissionClientImpl.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 NotificationPermissionClientImpl_h
 #define NotificationPermissionClientImpl_h
 
 #include "modules/notifications/NotificationPermissionClient.h"
 
 namespace blink {
 
 class NotificationPermissionClientImpl : public NoBaseWillBeGarbageCollectedFinalized<NotificationPermissionClientImpl>, public NotificationPermissionClient {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(NotificationPermissionClientImpl);
 public:
     static PassOwnPtrWillBeRawPtr<NotificationPermissionClientImpl> create();
 
-    virtual ~NotificationPermissionClientImpl();
+    ~NotificationPermissionClientImpl() override;
 
     // NotificationPermissionClient implementation.
-    virtual void requestPermission(ExecutionContext*, NotificationPermissionCallback*) override;
+    void requestPermission(ExecutionContext*, NotificationPermissionCallback*) override;
 
     // NoBaseWillBeGarbageCollectedFinalized implementation.
     DEFINE_INLINE_VIRTUAL_TRACE() { NotificationPermissionClient::trace(visitor); }
 
 private:
     NotificationPermissionClientImpl();
 };
 
 } // namespace blink
 
 #endif // NotificationPermissionClientImpl_h