Remove unnecessary 'virtual' annotation from mojo

mojo/services/html_viewer/webstoragenamespace_impl.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 MOJO_SERVICES_HTML_VIEWER_WEBSTORAGENAMESPACE_IMPL_H_
 #define MOJO_SERVICES_HTML_VIEWER_WEBSTORAGENAMESPACE_IMPL_H_
 
 #include "base/macros.h"
 #include "third_party/WebKit/public/platform/WebStorageNamespace.h"
 
 namespace html_viewer {
 
 class WebStorageNamespaceImpl : public blink::WebStorageNamespace {
  public:
   WebStorageNamespaceImpl();
 
  private:
-  virtual ~WebStorageNamespaceImpl();
+  ~WebStorageNamespaceImpl() override;
 
   // blink::WebStorageNamespace methods:
-  virtual blink::WebStorageArea* createStorageArea(
-      const blink::WebString& origin);
-  virtual bool isSameNamespace(const blink::WebStorageNamespace&) const;
+  blink::WebStorageArea* createStorageArea(
+      const blink::WebString& origin) override;
+  bool isSameNamespace(const blink::WebStorageNamespace&) const override;
 
   DISALLOW_COPY_AND_ASSIGN(WebStorageNamespaceImpl);
 };
 
 }  // namespace html_viewer
 
 #endif  // MOJO_SERVICES_HTML_VIEWER_WEBSTORAGENAMESPACE_IMPL_H_