Enforce marking "override" for functions overriding Blink.

content/renderer/render_frame_impl.h

 // Copyright 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_RENDERER_RENDER_FRAME_IMPL_H_
 #define CONTENT_RENDERER_RENDER_FRAME_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 414 matching lines @@
       blink::WebSandboxFlags sandboxFlags,
       const blink::WebFrameOwnerProperties& frameOwnerProperties) override;
   void didChangeOpener(blink::WebFrame* frame) override;
   void frameDetached(blink::WebFrame* frame, DetachType type) override;
   void frameFocused() override;
   void willClose(blink::WebFrame* frame) override;
   void didChangeName(blink::WebLocalFrame* frame,
                      const blink::WebString& name) override;
   void didChangeSandboxFlags(blink::WebFrame* child_frame,
                              blink::WebSandboxFlags flags) override;
-  virtual void didChangeFrameOwnerProperties(
+  void didChangeFrameOwnerProperties(
       blink::WebFrame* child_frame,
       const blink::WebFrameOwnerProperties& frame_owner_properties) override;
   void didMatchCSS(
       blink::WebLocalFrame* frame,
       const blink::WebVector<blink::WebString>& newly_matching_selectors,
       const blink::WebVector<blink::WebString>& stopped_matching_selectors)
       override;
   bool shouldReportDetailedMessageForSource(
       const blink::WebString& source) override;
   void didAddMessageToConsole(const blink::WebConsoleMessage& message,
@@ skipping 671 matching lines @@
 #endif
 
   base::WeakPtrFactory<RenderFrameImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_FRAME_IMPL_H_