Virtual destructors should have virtual keyword.

chrome/browser/ui/webui/keyboard_ui.h

 // Copyright (c) 2011 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 CHROME_BROWSER_UI_WEBUI_KEYBOARD_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_KEYBOARD_UI_H_
 #pragma once
 
 #include <string>
 
 #include "chrome/browser/ui/webui/chrome_url_data_manager.h"
 #include "content/browser/webui/web_ui.h"
 
 class Profile;
 
 // The TabContents used for the keyboard page.
 class KeyboardUI : public WebUI {
  public:
   explicit KeyboardUI(TabContents* manager);
-  ~KeyboardUI();
+  virtual ~KeyboardUI();
 
   class KeyboardHTMLSource : public ChromeURLDataManager::DataSource {
    public:
     KeyboardHTMLSource();
 
     // Overrides from DataSource
     virtual void StartDataRequest(const std::string& path,
                                   bool is_incognito,
                                   int request_id);
     virtual std::string GetMimeType(const std::string&) const;
 
    private:
     virtual ~KeyboardHTMLSource() {}
 
     DISALLOW_COPY_AND_ASSIGN(KeyboardHTMLSource);
   };
 
  private:
   DISALLOW_COPY_AND_ASSIGN(KeyboardUI);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_KEYBOARD_UI_H_