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

Source/modules/navigatorcontentutils/testing/NavigatorContentUtilsClientMock.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 NavigatorContentUtilsClientMock_h
 #define NavigatorContentUtilsClientMock_h
 
 #include "modules/navigatorcontentutils/NavigatorContentUtilsClient.h"
 #include "wtf/HashSet.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class KURL;
 
 // Provides a mock object for the navigatorcontentutils client.
 class NavigatorContentUtilsClientMock : public NavigatorContentUtilsClient {
 public:
     NavigatorContentUtilsClientMock() { }
-    virtual ~NavigatorContentUtilsClientMock() { }
+    ~NavigatorContentUtilsClientMock() override { }
 
     virtual void registerProtocolHandler(const String& scheme, const KURL&, const String& title);
 
     virtual CustomHandlersState isProtocolHandlerRegistered(const String& scheme, const KURL&);
     virtual void unregisterProtocolHandler(const String& scheme, const KURL&);
 
 private:
     typedef struct {
         String scheme;
         KURL url;
         String title;
     } ProtocolInfo;
 
     typedef HashMap<String, ProtocolInfo> RegisteredProtocolMap;
     RegisteredProtocolMap m_protocolMap;
 };
 
 } // namespace blink
 
 #endif // NavigatorContentUtilsClientMock_h