Standardize usage of virtual/override/final in chrome/browser/

chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm

 // 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.
 
 #import "chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.h"
 
 #include <cmath>
 
 #include "base/prefs/pref_service.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 28 matching lines @@
 class SpellCheckObserver : public content::WebContentsObserver {
  public:
   SpellCheckObserver(
       RenderViewHost* host,
       ChromeRenderWidgetHostViewMacDelegate* view_delegate)
       : content::WebContentsObserver(
             content::WebContents::FromRenderViewHost(host)),
         view_delegate_(view_delegate) {
   }
 
-  virtual ~SpellCheckObserver() {
-  }
+  ~SpellCheckObserver() override {}
 
  private:
-  virtual bool OnMessageReceived(const IPC::Message& message) override {
+  bool OnMessageReceived(const IPC::Message& message) override {
     bool handled = true;
     IPC_BEGIN_MESSAGE_MAP(SpellCheckObserver, message)
       IPC_MESSAGE_HANDLER(SpellCheckHostMsg_ToggleSpellCheck,
                           OnToggleSpellCheck)
       IPC_MESSAGE_UNHANDLED(handled = false)
     IPC_END_MESSAGE_MAP()
     return handled;
   }
 
   void OnToggleSpellCheck(bool enabled, bool checked) {
@@ skipping 183 matching lines @@
 }
 
 - (void)spellCheckEnabled:(BOOL)enabled checked:(BOOL)checked {
   spellcheckEnabled_ = enabled;
   spellcheckChecked_ = checked;
 }
 
 // END Spellchecking methods
 
 @end