Prune shared extendion module after extension updating.

extensions/browser/extension_registry.h

 // Copyright 2013 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 EXTENSIONS_BROWSER_EXTENSION_REGISTRY_H_
 #define EXTENSIONS_BROWSER_EXTENSION_REGISTRY_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 70 matching lines @@
   // If true, |from_ephemeral| indicates that the extension was previously
   // installed ephemerally and has been promoted to a regular installed
   // extension. |is_update| should also be true.
   void TriggerOnWillBeInstalled(const Extension* extension,
                                 bool is_update,
                                 bool from_ephemeral,
                                 const std::string& old_name);
 
   // Invokes the observer method OnExtensionInstalled(). The extension must be
   // contained in one of the registry's extension sets.
-  void TriggerOnInstalled(const Extension* extension);
+  void TriggerOnInstalled(const Extension* extension,
+                          bool is_update);
 
   // Invokes the observer method OnExtensionUninstalled(). The extension must
   // not be any installed extension with |extension|'s ID.
   void TriggerOnUninstalled(const Extension* extension);
 
   // Find an extension by ID using |include_mask| to pick the sets to search:
   //  * enabled_extensions()     --> ExtensionRegistry::ENABLED
   //  * disabled_extensions()    --> ExtensionRegistry::DISABLED
   //  * terminated_extensions()  --> ExtensionRegistry::TERMINATED
   //  * blacklisted_extensions() --> ExtensionRegistry::BLACKLISTED
@@ skipping 57 matching lines @@
   ObserverList<ExtensionRegistryObserver> observers_;
 
   content::BrowserContext* const browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionRegistry);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_REGISTRY_H_