Move ExtensionSystem into extensions namespace

chrome/browser/extensions/extension_service.h

Index: chrome/browser/extensions/extension_service.h
diff --git a/chrome/browser/extensions/extension_service.h b/chrome/browser/extensions/extension_service.h
index c2b00899bc23aaffef231cdb48ba417fcc997b47..8501f2c6f8a1fefe6615a4d57747395cb2b61f79 100644
--- a/chrome/browser/extensions/extension_service.h
+++ b/chrome/browser/extensions/extension_service.h
@@ -58,7 +58,6 @@ class ExtensionManagedModeEventRouter;
 class ExtensionManagementEventRouter;
 class ExtensionPreferenceEventRouter;
 class ExtensionSyncData;
-class ExtensionSystem;
 class ExtensionToolbarModel;
 class HistoryExtensionEventRouter;
 class GURL;
@@ -83,6 +82,7 @@ class ContentSettingsStore;
 class Extension;
 class ExtensionCookiesEventRouter;
 class ExtensionSyncData;
+class ExtensionSystem;
 class ExtensionUpdater;
 class SettingsFrontend;
 class WebNavigationEventRouter;
@@ -709,7 +709,7 @@ class ExtensionService
   Profile* profile_;
 
   // The ExtensionSystem for the profile above.
-  ExtensionSystem* system_;
+  extensions::ExtensionSystem* system_;
 
   // Preferences for the owning profile (weak reference).
   ExtensionPrefs* extension_prefs_;