Remove the last usages of PrefObserver outside of Prefs.

chrome/browser/profiles/profile_impl_io_data.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/profiles/profile_impl_io_data.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/logging.h"
@@ skipping 252 matching lines @@
   if (initialized_)
     return;
 
   // Set initialized_ to true at the beginning in case any of the objects
   // below try to get the ResourceContext pointer.
   initialized_ = true;
   PrefService* pref_service = profile_->GetPrefs();
   io_data_->set_http_server_properties_manager(
       new chrome_browser_net::HttpServerPropertiesManager(pref_service));
   io_data_->session_startup_pref()->Init(
-      prefs::kRestoreOnStartup, pref_service, NULL);
+      prefs::kRestoreOnStartup, pref_service);
   io_data_->session_startup_pref()->MoveToThread(
       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
 #if defined(FULL_SAFE_BROWSING) || defined(MOBILE_SAFE_BROWSING)
   io_data_->safe_browsing_enabled()->Init(prefs::kSafeBrowsingEnabled,
-      pref_service, NULL);
+      pref_service);
   io_data_->safe_browsing_enabled()->MoveToThread(
       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
 #endif
   io_data_->InitializeOnUIThread(profile_);
 }
 
 ProfileImplIOData::LazyParams::LazyParams()
     : cache_max_size(0),
       media_cache_max_size(0),
       restore_old_session_cookies(false) {}
@@ skipping 387 matching lines @@
     base::Time time,
     const base::Closure& completion) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   LazyInitialize();
 
   DCHECK(transport_security_state());
   transport_security_state()->DeleteSince(time);  // Completes synchronously.
   DCHECK(http_server_properties_manager());
   http_server_properties_manager()->Clear(completion);
 }