Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/webui/ntp/ntp_resource_cache.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_WEBUI_NTP_NTP_RESOURCE_CACHE_H_
 #define CHROME_BROWSER_UI_WEBUI_NTP_NTP_RESOURCE_CACHE_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "base/string16.h"
 #include "chrome/browser/profiles/profile_keyed_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class Profile;
 
 namespace base {
 class RefCountedMemory;
 }
 
 namespace ui {
 class ThemeProvider;
 }
 
 // This class keeps a cache of NTP resources (HTML and CSS) so we don't have to
 // regenerate them all the time.
 class NTPResourceCache : public content::NotificationObserver,
+                         public PrefObserver,
                          public ProfileKeyedService {
  public:
   explicit NTPResourceCache(Profile* profile);
   virtual ~NTPResourceCache();
 
   base::RefCountedMemory* GetNewTabHTML(bool is_incognito);
   base::RefCountedMemory* GetNewTabCSS(bool is_incognito);
 
   // content::NotificationObserver interface.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // PrefObserver interface.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
+
   // Returns the CSS background-position-y style for new_tab_theme.css:
   // - |y_pos| is the vertical offset of theme image in content view.
   // - |alignment| is alignment of theme image.
   static std::string GetNewTabBackgroundPositionY(int y_pos, int alignment);
 
  private:
   Profile* profile_;
 
   void CreateNewTabHTML();
   scoped_refptr<base::RefCountedMemory> new_tab_html_;
@@ skipping 33 matching lines @@
 
   // Y-pos of |background_position| of new_tab_theme.css notified from
   // |SearchViewController| via
   // chrome::NOTIFICATION_NTP_BACKGROUND_THEME_Y_POS_CHANGED.
   int css_background_y_pos_;
 
   DISALLOW_COPY_AND_ASSIGN(NTPResourceCache);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_NTP_RESOURCE_CACHE_H_