Use ExtensionRegistryObserver instead of deprecated extension notification from c/b/extension

chrome/browser/extensions/extension_gcm_app_handler.h

Index: chrome/browser/extensions/extension_gcm_app_handler.h
diff --git a/chrome/browser/extensions/extension_gcm_app_handler.h b/chrome/browser/extensions/extension_gcm_app_handler.h
index 5da91b71d05697e282bc1532e4c60a9fcdca5527..8bff0a77fe282a3b2a76cf35a12bff9b2b118416 100644
--- a/chrome/browser/extensions/extension_gcm_app_handler.h
+++ b/chrome/browser/extensions/extension_gcm_app_handler.h
@@ -13,8 +13,6 @@
 #include "base/memory/weak_ptr.h"
 #include "base/scoped_observer.h"
 #include "components/gcm_driver/gcm_app_handler.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 #include "extensions/browser/browser_context_keyed_api_factory.h"
 #include "extensions/browser/extension_registry_observer.h"
 #include "google_apis/gcm/gcm_client.h"
@@ -38,7 +36,6 @@ class GcmJsEventRouter;
 // Defines the interface to provide handling logic for a given app.
 class ExtensionGCMAppHandler : public gcm::GCMAppHandler,
                                public BrowserContextKeyedAPI,
-                               public content::NotificationObserver,
                                public ExtensionRegistryObserver {
  public:
   explicit ExtensionGCMAppHandler(content::BrowserContext* context);
@@ -65,11 +62,6 @@ class ExtensionGCMAppHandler : public gcm::GCMAppHandler,
  private:
   friend class BrowserContextKeyedAPIFactory<ExtensionGCMAppHandler>;
 
-  // content::NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
-
   // ExtensionRegistryObserver implementation.
   virtual void OnExtensionLoaded(content::BrowserContext* browser_context,
                                  const Extension* extension) OVERRIDE;
@@ -77,6 +69,8 @@ class ExtensionGCMAppHandler : public gcm::GCMAppHandler,
       content::BrowserContext* browser_context,
       const Extension* extension,
       UnloadedExtensionInfo::Reason reason) OVERRIDE;
+  virtual void OnExtensionUninstalled(content::BrowserContext* browser_context,
+                                      const Extension* extension) OVERRIDE;
 
   gcm::GCMDriver* GetGCMDriver() const;
 
@@ -85,7 +79,6 @@ class ExtensionGCMAppHandler : public gcm::GCMAppHandler,
   static const bool kServiceIsNULLWhileTesting = true;
 
   Profile* profile_;
-  content::NotificationRegistrar registrar_;
 
   // Listen to extension load, unloaded notifications.
   ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>