Standardize usage of virtual/override/final in extensions/

extensions/renderer/messaging_bindings.cc

 // 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.
 
 #include "extensions/renderer/messaging_bindings.h"
 
 #include <map>
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 83 matching lines @@
         "PortRelease",
         base::Bind(&ExtensionImpl::PortRelease, base::Unretained(this)));
     RouteFunction(
         "PostMessage",
         base::Bind(&ExtensionImpl::PostMessage, base::Unretained(this)));
     // TODO(fsamuel, kalman): Move BindToGC out of messaging natives.
     RouteFunction("BindToGC",
                   base::Bind(&ExtensionImpl::BindToGC, base::Unretained(this)));
   }
 
-  virtual ~ExtensionImpl() {}
+  ~ExtensionImpl() override {}
 
  private:
   void ClearPortDataAndNotifyDispatcher(int port_id) {
     ClearPortData(port_id);
     dispatcher_->ClearPortData(port_id);
   }
 
   // Sends a message along the given channel.
   void PostMessage(const v8::FunctionCallbackInfo<v8::Value>& args) {
     content::RenderView* renderview = context()->GetRenderView();
@@ skipping 310 matching lines @@
     const ScriptContextSet& context_set,
     int port_id,
     const std::string& error_message,
     content::RenderView* restrict_to_render_view) {
   context_set.ForEach(
       restrict_to_render_view,
       base::Bind(&DispatchOnDisconnectToScriptContext, port_id, error_message));
 }
 
 }  // namespace extensions