Remove NOTIFICATION_EXTENSION_UNLOADED from system_indicator API.

chrome/browser/extensions/api/system_indicator/system_indicator_manager.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_API_SYSTEM_INDICATOR_SYSTEM_INDICATOR_MANAGER_H_
 #define CHROME_BROWSER_EXTENSIONS_API_SYSTEM_INDICATOR_SYSTEM_INDICATOR_MANAGER_H_
 
 #include <map>
 #include <string>
 
 #include "base/memory/linked_ptr.h"
+#include "base/scoped_observer.h"
 #include "base/threading/thread_checker.h"
 #include "chrome/browser/extensions/extension_action_icon_factory.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
-#include "extensions/browser/event_router.h"
+#include "extensions/browser/extension_registry_observer.h"
 
 class ExtensionAction;
 class Profile;
 class StatusTray;
 
 FORWARD_DECLARE_TEST(SystemIndicatorApiTest, SystemIndicator);
 
 namespace extensions {
-
 class ExtensionIndicatorIcon;
+class ExtensionRegistry;
 
 // Keeps track of all the systemIndicator icons created for a given Profile
 // that are currently visible in the UI.  Use SystemIndicatorManagerFactory to
 // create a SystemIndicatorManager object.
 class SystemIndicatorManager : public content::NotificationObserver,
+                               public ExtensionRegistryObserver,
                                public KeyedService {
  public:
   SystemIndicatorManager(Profile* profile, StatusTray* status_tray);
   virtual ~SystemIndicatorManager();
 
   // KeyedService implementation.
   virtual void Shutdown() OVERRIDE;
 
+ private:
+  FRIEND_TEST_ALL_PREFIXES(::SystemIndicatorApiTest, SystemIndicator);
+
   // content::NotificationDelegate implementation.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
- private:
-  FRIEND_TEST_ALL_PREFIXES(::SystemIndicatorApiTest, SystemIndicator);
+  // ExtensionRegistryObserver implementation.
+  virtual void OnExtensionUnloaded(
+      content::BrowserContext* browser_context,
+      const Extension* extension,
+      UnloadedExtensionInfo::Reason reason) OVERRIDE;
 
   // Determines whether the indicator should be hidden or shown and calls the
   // appropriate function.
   void OnSystemIndicatorChanged(const ExtensionAction* extension_action);
 
   // Causes a call to OnStatusIconClicked for the specified extension_id.
   // Returns false if no ExtensionIndicatorIcon is found for the extension.
   bool SendClickEventToExtensionForTest(const std::string extension_id);
 
   // Causes an indicator to be shown for the given extension_action.  Creates
   // the indicator if necessary.
   void CreateOrUpdateIndicator(
       const Extension* extension,
       const ExtensionAction* extension_action);
 
   // Causes the indicator for the given extension to be hidden.
   void RemoveIndicator(const std::string &extension_id);
 
   typedef std::map<const std::string, linked_ptr<ExtensionIndicatorIcon> >
       SystemIndicatorMap;
 
   Profile* profile_;
   StatusTray* status_tray_;
   SystemIndicatorMap system_indicators_;
   content::NotificationRegistrar registrar_;
   base::ThreadChecker thread_checker_;
 
+  // Listen to extension unloaded notifications.
+  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
+      extension_registry_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(SystemIndicatorManager);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_SYSTEM_INDICATOR_SYSTEM_INDICATOR_MANAGER_H_