RefCounted types should not have public destructors, delegate cleanup

chrome/browser/extensions/webstore_install_helper.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_WEBSTORE_INSTALL_HELPER_H_
 #define CHROME_BROWSER_EXTENSIONS_WEBSTORE_INSTALL_HELPER_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 40 matching lines @@
         const std::string& id,
         const SkBitmap& icon,
         base::DictionaryValue* parsed_manifest) = 0;
 
     // Called to indicate a parse failure. The |result_code| parameter should
     // indicate whether the problem was with the manifest or icon.
     virtual void OnWebstoreParseFailure(
         const std::string& id,
         InstallHelperResultCode result_code,
         const std::string& error_message) = 0;
+
+   protected:
+    virtual ~Delegate() {}
   };
 
   // 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& id,
                         const std::string& manifest,
                         const std::string& icon_data,
                         const GURL& icon_url,
                         net::URLRequestContextGetter* context_getter);
@@ skipping 52 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_