Make kCookiePromptExpanded a profile pref rather than a local state pref so it can be synced.

chrome/browser/cookie_modal_dialog.cc

 // Copyright (c) 2010 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/cookie_modal_dialog.h"
 
 #include "app/message_box_flags.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/host_content_settings_map.h"
 #include "chrome/browser/pref_service.h"
@@ skipping 119 matching lines @@
         CONTENT_SETTINGS_TYPE_COOKIES, CONTENT_SETTING_BLOCK);
   }
 
   if (delegate_) {
     delegate_->BlockSiteData();
     delegate_ = NULL;  // It can be deleted at any point now.
   }
 }
 
 // static
-void CookiePromptModalDialog::RegisterPrefs(PrefService* prefs) {
+void CookiePromptModalDialog::RegisterUserPrefs(PrefService* prefs) {
   prefs->RegisterBooleanPref(prefs::kCookiePromptExpanded, false);
 }
 
 int CookiePromptModalDialog::GetDialogButtons() {
   // Enable the automation interface to accept/dismiss this dialog.
   return MessageBoxFlags::DIALOGBUTTON_OK |
          MessageBoxFlags::DIALOGBUTTON_CANCEL;
 }