Modify ThreadChecker and NonThreadSafe so that their functionality is

base/threading/thread_checker_impl.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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 "base/threading/thread_checker.h"
-
-// This code is only done in debug builds.
-#ifndef NDEBUG
+#include "base/threading/thread_checker_impl.h"
 
 namespace base {
 
-ThreadChecker::ThreadChecker() : valid_thread_id_(kInvalidThreadId) {
+ThreadCheckerImpl::ThreadCheckerImpl()
+    : valid_thread_id_(kInvalidThreadId) {
   EnsureThreadIdAssigned();
 }
 
-ThreadChecker::~ThreadChecker() {}
+ThreadCheckerImpl::~ThreadCheckerImpl() {}
 
-bool ThreadChecker::CalledOnValidThread() const {
+bool ThreadCheckerImpl::CalledOnValidThread() const {
   EnsureThreadIdAssigned();
   AutoLock auto_lock(lock_);
   return valid_thread_id_ == PlatformThread::CurrentId();
 }
 
-void ThreadChecker::DetachFromThread() {
+void ThreadCheckerImpl::DetachFromThread() {
   AutoLock auto_lock(lock_);
   valid_thread_id_ = kInvalidThreadId;
 }
 
-void ThreadChecker::EnsureThreadIdAssigned() const {
+void ThreadCheckerImpl::EnsureThreadIdAssigned() const {
   AutoLock auto_lock(lock_);
   if (valid_thread_id_ != kInvalidThreadId)
     return;
   valid_thread_id_ = PlatformThread::CurrentId();
 }
 
 }  // namespace base
-
-#endif  // NDEBUG