Remove the last usages of PrefObserver outside of Prefs.

chrome/browser/spellchecker/spellcheck_service.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/spellchecker/spellcheck_service.h"
 
 #include "base/platform_file.h"
 #include "base/string_split.h"
 #include "base/synchronization/waitable_event.h"
 #include "chrome/browser/api/prefs/pref_member.h"
@@ skipping 61 matching lines @@
   // Remove pref observers
   pref_change_registrar_.RemoveAll();
 }
 
 // static
 int SpellcheckService::GetSpellCheckLanguages(
     Profile* profile,
     std::vector<std::string>* languages) {
   StringPrefMember accept_languages_pref;
   StringPrefMember dictionary_language_pref;
-  accept_languages_pref.Init(prefs::kAcceptLanguages, profile->GetPrefs(),
-                             NULL);
+  accept_languages_pref.Init(prefs::kAcceptLanguages, profile->GetPrefs());
   dictionary_language_pref.Init(prefs::kSpellCheckDictionary,
-                                profile->GetPrefs(), NULL);
+                                profile->GetPrefs());
   std::string dictionary_language = dictionary_language_pref.GetValue();
 
   // Now scan through the list of accept languages, and find possible mappings
   // from this list to the existing list of spell check languages.
   std::vector<std::string> accept_languages;
 
 #if defined(OS_MACOSX)
   if (spellcheck_mac::SpellCheckerAvailable())
     spellcheck_mac::GetAvailableLanguages(&accept_languages);
   else
@@ skipping 140 matching lines @@
 }
 
 // static
 SpellcheckService::EventType SpellcheckService::WaitStatusEvent() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   if (g_status_event)
     g_status_event->Wait();
   return g_status_type;
 }