Fix crash in bundle install dialog.

chrome/browser/extensions/extension_install_prompt.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_EXTENSION_INSTALL_PROMPT_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_INSTALL_PROMPT_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 268 matching lines @@
   // Shows the actual UI (the icon should already be loaded).
   void ShowConfirmation();
 
   gfx::NativeWindow parent_;
   content::PageNavigator* navigator_;
   MessageLoop* ui_loop_;
 
   // The extensions installation icon.
   SkBitmap icon_;
 
-  // The extension we are showing the UI for.
+  // The extension we are showing the UI for, if type is not
+  // BUNDLE_INSTALL_PROMPT.
   const extensions::Extension* extension_;
 
   // The bundle we are showing the UI for, if type BUNDLE_INSTALL_PROMPT.
   const extensions::BundleInstaller* bundle_;
 
   // The permissions being prompted for.
   scoped_refptr<const extensions::PermissionSet> permissions_;
 
   // The object responsible for doing the UI specific actions.
   scoped_ptr<ExtensionInstallUI> install_ui_;
@@ skipping 18 matching lines @@
 
 // Creates an ExtensionInstallPrompt from |browser|. Caller assumes ownership.
 // TODO(beng): remove this once various extensions types are weaned from
 //             Browser.
 ExtensionInstallPrompt* CreateExtensionInstallPromptWithBrowser(
     Browser* browser);
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_INSTALL_PROMPT_H_