[Cleanup] Const-correct the profile() method for the EasyUnlockService

chrome/browser/profiles/profile_impl.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.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 921 matching lines @@
 }
 
 Profile::ExitType ProfileImpl::GetLastSessionExitType() {
   // last_session_exited_cleanly_ is set when the preferences are loaded. Force
   // it to be set by asking for the prefs.
   GetPrefs();
   return last_session_exit_type_;
 }
 
 PrefService* ProfileImpl::GetPrefs() {
+  return const_cast<PrefService*>(
+      static_cast<const ProfileImpl*>(this)->GetPrefs());
+}
+
+const PrefService* ProfileImpl::GetPrefs() const {
   DCHECK(prefs_);  // Should explicitly be initialized.
   return prefs_.get();
 }
 
 chrome::ChromeZoomLevelPrefs* ProfileImpl::GetZoomLevelPrefs() {
   return static_cast<chrome::ChromeZoomLevelPrefs*>(
       GetDefaultStoragePartition(this)->GetZoomLevelDelegate());
 }
 
 PrefService* ProfileImpl::GetOffTheRecordPrefs() {
@@ skipping 371 matching lines @@
 ProfileImpl::CreateDomainReliabilityMonitor(PrefService* local_state) {
   domain_reliability::DomainReliabilityService* service =
       domain_reliability::DomainReliabilityServiceFactory::GetInstance()->
           GetForBrowserContext(this);
   if (!service)
     return scoped_ptr<domain_reliability::DomainReliabilityMonitor>();
 
   return service->CreateMonitor(
       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
 }