Virtual destructors should have virtual keyword.

chrome/browser/extensions/extensions_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_EXTENSIONS_EXTENSIONS_UI_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSIONS_UI_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 36 matching lines @@
   ExtensionsUIHTMLSource();
 
   // Called when the network layer has requested a resource underneath
   // the path we registered.
   virtual void StartDataRequest(const std::string& path,
                                 bool is_incognito,
                                 int request_id);
   virtual std::string GetMimeType(const std::string&) const;
 
  private:
-  ~ExtensionsUIHTMLSource() {}
+  virtual ~ExtensionsUIHTMLSource() {}
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionsUIHTMLSource);
 };
 
 // The handler for JavaScript messages related to the "extensions" view.
 class ExtensionsDOMHandler : public WebUIMessageHandler,
                              public NotificationObserver,
                              public PackExtensionJob::Client,
                              public SelectFileDialog::Listener,
                              public ExtensionUninstallDialog::Delegate {
@@ skipping 142 matching lines @@
 
   static RefCountedMemory* GetFaviconResourceBytes();
 
   static void RegisterUserPrefs(PrefService* prefs);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ExtensionsUI);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSIONS_UI_H_