Revert 124817 - Take extensions out of Profile into a profile-keyed service, ExtensionSystem.

chrome/browser/extensions/extension_service.h

Index: chrome/browser/extensions/extension_service.h
===================================================================
--- chrome/browser/extensions/extension_service.h	(revision 124830)
+++ chrome/browser/extensions/extension_service.h	(working copy)
@@ -58,7 +58,6 @@
 class ExtensionManagementEventRouter;
 class ExtensionPreferenceEventRouter;
 class ExtensionSyncData;
-class ExtensionSystem;
 class ExtensionToolbarModel;
 class ExtensionUpdater;
 class ExtensionWebNavigationEventRouter;
@@ -707,12 +706,9 @@
 
   NaClModuleInfoList::iterator FindNaClModule(const GURL& url);
 
-  // The normal profile associated with this ExtensionService.
+  // The profile this ExtensionService is part of.
   Profile* profile_;
 
-  // The ExtensionSystem for the profile above.
-  ExtensionSystem* system_;
-
   // Preferences for the owning profile (weak reference).
   ExtensionPrefs* extension_prefs_;