Remove NOTIFICATION_EXTENSION_ENABLED.

chrome/browser/themes/theme_service.h

Index: chrome/browser/themes/theme_service.h
diff --git a/chrome/browser/themes/theme_service.h b/chrome/browser/themes/theme_service.h
index 51c676c2d0f337cf06f18469e8f6ed485942581e..76d1232318827aad266a2b0ae884750d8de6d462 100644
--- a/chrome/browser/themes/theme_service.h
+++ b/chrome/browser/themes/theme_service.h
@@ -300,13 +300,6 @@ class ThemeService : public content::NotificationObserver, public KeyedService {
 
   scoped_refptr<CustomThemeSupplier> theme_supplier_;
 
-  // The id of the theme extension which has just been installed but has not
-  // been loaded yet. The theme extension with |installed_pending_load_id_| may
-  // never be loaded if the install is due to updating a disabled theme.
-  // |pending_install_id_| should be set to |kDefaultThemeID| if there are no
-  // recently installed theme extensions
-  std::string installed_pending_load_id_;
-
   // The number of infobars currently displayed.
   int number_of_infobars_;