Prune shared extendion module after extension updating.

chrome/browser/extensions/webstore_installer.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_INSTALLER_H_
 #define CHROME_BROWSER_EXTENSIONS_WEBSTORE_INSTALLER_H_
 
 #include <list>
 #include <string>
 
@@ skipping 182 matching lines @@
   // Starts downloading and installing the extension.
   void Start();
 
   // content::NotificationObserver.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
   // ExtensionRegistryObserver.
   virtual void OnExtensionInstalled(content::BrowserContext* browser_context,
-                                    const Extension* extension) OVERRIDE;
+                                    const Extension* extension,
+                                    bool is_update) OVERRIDE;
 
   // Removes the reference to the delegate passed in the constructor. Used when
   // the delegate object must be deleted before this object.
   void InvalidateDelegate();
 
   // Instead of using the default download directory, use |directory| instead.
   // This does *not* transfer ownership of |directory|.
   static void SetDownloadDirectoryForTests(base::FilePath* directory);
 
  private:
@@ skipping 65 matching lines @@
   std::list<SharedModuleInfo::ImportInfo> pending_modules_;
   // Total extension modules we need download and install (the main module and
   // depedences).
   int total_modules_;
   bool download_started_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_WEBSTORE_INSTALLER_H_