Warn on missing OVERRIDE/virtual everywhere, not just in header files.

ash/shell/app_list.cc

 // Copyright (c) 2012 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 <string>
 
 #include "ash/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell/example_factory.h"
 #include "ash/shell/toplevel_window.h"
@@ skipping 277 matching lines @@
   }
 
   virtual void ViewActivationChanged(bool active) OVERRIDE {
     // Nothing needs to be done.
   }
 
   virtual gfx::ImageSkia GetWindowIcon() OVERRIDE {
     return gfx::ImageSkia();
   }
 
-  virtual base::string16 GetCurrentUserName() {
+  virtual base::string16 GetCurrentUserName() OVERRIDE {
     return base::string16();
   }
 
-  virtual base::string16 GetCurrentUserEmail() {
+  virtual base::string16 GetCurrentUserEmail() OVERRIDE {
     return base::string16();
   }
 
-  virtual void OpenSettings() {
+  virtual void OpenSettings() OVERRIDE {
     // Nothing needs to be done.
   }
 
-  virtual void OpenFeedback() {
+  virtual void OpenFeedback() OVERRIDE {
     // Nothing needs to be done.
   }
 
   app_list::AppListModel* model_;
 
   DISALLOW_COPY_AND_ASSIGN(ExampleAppListViewDelegate);
 };
 
 }  // namespace
 
 app_list::AppListViewDelegate* CreateAppListViewDelegate() {
   return new ExampleAppListViewDelegate;
 }
 
 }  // namespace shell
 }  // namespace ash