[Cleanup] Remove StringPrintf from global namespace

chrome/browser/notifications/notification_object_proxy.cc

 // 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.
 
 #include "chrome/browser/notifications/notification_object_proxy.h"
 
 #include "base/stringprintf.h"
 #include "content/public/browser/render_view_host.h"
 
 using content::RenderViewHost;
@@ skipping 28 matching lines @@
     host->DesktopNotificationPostClose(notification_id_, by_user);
 }
 
 void NotificationObjectProxy::Click() {
   RenderViewHost* host = RenderViewHost::FromID(process_id_, route_id_);
   if (host)
     host->DesktopNotificationPostClick(notification_id_);
 }
 
 std::string NotificationObjectProxy::id() const {
-  return StringPrintf("%d:%d:%d:%d", process_id_, route_id_,
-                      notification_id_, worker_);
+  return base::StringPrintf("%d:%d:%d:%d", process_id_, route_id_,
+                            notification_id_, worker_);
 }
 
 RenderViewHost* NotificationObjectProxy::GetRenderViewHost() const {
   return RenderViewHost::FromID(process_id_, route_id_);
 }