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

ui/app_list/views/app_list_menu_views.cc

 // 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.
 
 #include "ui/app_list/views/app_list_menu_views.h"
 
 #include "grit/ui_resources.h"
 #include "ui/app_list/app_list_view_delegate.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/views/controls/button/menu_button.h"
@@ skipping 76 matching lines @@
 
 class AppListMenuModelAdapter : public views::MenuModelAdapter {
  public:
   AppListMenuModelAdapter(ui::MenuModel* menu_model,
                           AppListViewDelegate* delegate)
       : views::MenuModelAdapter(menu_model),
         delegate_(delegate) {}
   virtual ~AppListMenuModelAdapter() {}
 
   // Overridden from views::MenuModelAdapter:
-  MenuItemView* AppendMenuItem(MenuItemView* menu,
-                               ui::MenuModel* model,
-                               int index) OVERRIDE {
+  virtual MenuItemView* AppendMenuItem(MenuItemView* menu,
+                                       ui::MenuModel* model,
+                                       int index) OVERRIDE {
     if (!delegate_)
       return NULL;
 
     int id = model->GetCommandIdAt(index);
     if (id != AppListMenu::CURRENT_USER)
       return MenuModelAdapter::AppendMenuItem(menu, model, index);
 
     ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
     MenuItemView* item = new CurrentUserMenuItem(
         menu,
@@ skipping 29 matching lines @@
   ignore_result(menu_runner_->RunMenuAt(button->GetWidget(), button,
                                         gfx::Rect(point, gfx::Size()),
                                         MenuItemView::TOPRIGHT, 0));
 }
 
 void AppListMenuViews::Cancel() {
   menu_runner_->Cancel();
 }
 
 }  // namespace app_list