Destructor needs to be virtual.

chrome/browser/extensions/webstore_install_helper.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_WEBSTORE_INSTALL_HELPER_H_
 #define CHROME_BROWSER_EXTENSIONS_WEBSTORE_INSTALL_HELPER_H_
 #pragma once
 
 #include "content/browser/utility_process_host.h"
 #include "content/common/url_fetcher.h"
@@ skipping 39 matching lines @@
   // Only one of |icon_data| (based64-encoded icon data) or |icon_url| can be
   // specified, but it is legal for both to be empty.
   WebstoreInstallHelper(Delegate* delegate,
                         const std::string& manifest,
                         const std::string& icon_data,
                         const GURL& icon_url,
                         net::URLRequestContextGetter* context_getter);
   void Start();
 
  private:
-  ~WebstoreInstallHelper();
+  virtual ~WebstoreInstallHelper();
 
   void StartWorkOnIOThread();
   void StartFetchedImageDecode();
   void ReportResultsIfComplete();
   void ReportResultFromUIThread();
 
   // Implementing the URLFetcher::Delegate interface.
   virtual void OnURLFetchComplete(const URLFetcher* source) OVERRIDE;
 
   // Implementing pieces of the UtilityProcessHost::Client interface.
@@ skipping 35 matching lines @@
 
   // A details string for keeping track of any errors.
   std::string error_;
 
   // A code to distinguish between an error with the icon, and an error with the
   // manifest.
   Delegate::InstallHelperResultCode parse_error_;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_WEBSTORE_INSTALL_HELPER_H_