Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/printing/cloud_print/cloud_print_proxy_service.h

Index: chrome/browser/printing/cloud_print/cloud_print_proxy_service.h
diff --git a/chrome/browser/printing/cloud_print/cloud_print_proxy_service.h b/chrome/browser/printing/cloud_print/cloud_print_proxy_service.h
index 99bee151cab1f1b315cb7c00eba502e16346770b..e12a942ce77ce87b231239ccf631eee2830440a4 100644
--- a/chrome/browser/printing/cloud_print/cloud_print_proxy_service.h
+++ b/chrome/browser/printing/cloud_print/cloud_print_proxy_service.h
@@ -13,9 +13,9 @@
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "chrome/browser/printing/cloud_print/cloud_print_setup_handler.h"
 #include "chrome/browser/profiles/profile_keyed_service.h"
-#include "content/public/browser/notification_observer.h"
 
 class Profile;
 class ServiceProcessControl;
@@ -29,7 +29,7 @@ struct CloudPrintProxyInfo;
 class CloudPrintProxyService
     : public CloudPrintSetupHandlerDelegate,
       public ProfileKeyedService,
-      public content::NotificationObserver {
+      public PrefObserver {
  public:
   explicit CloudPrintProxyService(Profile* profile);
   virtual ~CloudPrintProxyService();
@@ -63,10 +63,9 @@ class CloudPrintProxyService
   // CloudPrintSetupHandler::Delegate implementation.
   virtual void OnCloudPrintSetupClosed() OVERRIDE;
 
-  // content::NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
+  // PrefObserver implementation.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
 
  private:
   // NotificationDelegate implementation for the token expired notification.