Use ExtensionRegistryObserver instead of deprecated extension notification from c/b/e/api.

chrome/browser/extensions/api/idle/idle_manager.h

Index: chrome/browser/extensions/api/idle/idle_manager.h
diff --git a/chrome/browser/extensions/api/idle/idle_manager.h b/chrome/browser/extensions/api/idle/idle_manager.h
index e93b0b23248668f809ac6df46de785ed97d50635..4752917ecd840ff50946912ff73688c4ff39a498 100644
--- a/chrome/browser/extensions/api/idle/idle_manager.h
+++ b/chrome/browser/extensions/api/idle/idle_manager.h
@@ -11,13 +11,13 @@
 #include "base/callback_forward.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
+#include "base/scoped_observer.h"
 #include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/idle.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"
 
 namespace base {
 class StringValue;
@@ -26,6 +26,7 @@ class StringValue;
 class Profile;
 
 namespace extensions {
+class ExtensionRegistry;
 
 typedef base::Callback<void(IdleState)> QueryStateCallback;
 
@@ -37,7 +38,7 @@ struct IdleMonitor {
   int threshold;
 };
 
-class IdleManager : public content::NotificationObserver,
+class IdleManager : public ExtensionRegistryObserver,
                     public EventRouter::Observer,
                     public KeyedService {
  public:
@@ -75,10 +76,11 @@ class IdleManager : public content::NotificationObserver,
   // KeyedService implementation.
   virtual void Shutdown() OVERRIDE;
 
-  // content::NotificationDelegate implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
+  // ExtensionRegistryObserver implementation.
+  virtual void OnExtensionUnloaded(
+      content::BrowserContext* browser_context,
+      const Extension* extension,
+      UnloadedExtensionInfo::Reason reason) OVERRIDE;
 
   // EventRouter::Observer implementation.
   virtual void OnListenerAdded(const EventListenerInfo& details) OVERRIDE;
@@ -125,13 +127,16 @@ class IdleManager : public content::NotificationObserver,
 
   base::RepeatingTimer<IdleManager> poll_timer_;
   base::WeakPtrFactory<IdleManager> weak_factory_;
-  content::NotificationRegistrar registrar_;
 
   scoped_ptr<IdleTimeProvider> idle_time_provider_;
   scoped_ptr<EventDelegate> event_delegate_;
 
   base::ThreadChecker thread_checker_;
 
+  // Listen to extension unloaded notification.
+  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
+      extension_registry_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(IdleManager);
 };