Revert changes to have ExtensionService notify ThemeService directly

chrome/browser/ui/gtk/gtk_theme_service.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_GTK_GTK_THEME_SERVICE_H_
 #define CHROME_BROWSER_UI_GTK_GTK_THEME_SERVICE_H_
 
 #include <map>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/public/pref_change_registrar.h"
 #include "chrome/browser/themes/theme_service.h"
 #include "ui/base/glib/glib_integers.h"
 #include "ui/base/gtk/gtk_signal.h"
 #include "ui/base/gtk/owned_widget_gtk.h"
 #include "ui/gfx/color_utils.h"
 
 class Profile;
 
-namespace content {
-class NotificationObserver;
-}
-
 namespace extensions {
 class Extension;
 }
 
 namespace gfx {
 class CairoCachedSurface;
 }
 
 namespace ui {
 class GtkSignalRegistrar;
@@ skipping 268 matching lines @@
 
   // The default folder icon and default bookmark icon for the GTK theme.
   // These are static because the system can only have one theme at a time.
   // They are cached when they are requested the first time, and cleared when
   // the system theme changes.
   static base::LazyInstance<gfx::Image> default_folder_icon_;
   static base::LazyInstance<gfx::Image> default_bookmark_icon_;
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_GTK_THEME_SERVICE_H_