Add missing base::lock usage.

ceee/testing/utils/instance_count_mixin.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.
 //
 // Implementation of instance count mixin base class.
 #include "ceee/testing/utils/instance_count_mixin.h"
 #include "base/logging.h"
 #include "gtest/gtest.h"
 
 namespace {
 // Set of existing instances.
 testing::InstanceCountMixinBase::InstanceSet instances;
 };
 
 namespace testing {
 
-Lock InstanceCountMixinBase::lock_;
+base::Lock InstanceCountMixinBase::lock_;
 
 InstanceCountMixinBase::InstanceCountMixinBase() {
   base::AutoLock lock(lock_);
 
   instances.insert(this);
 }
 
 InstanceCountMixinBase::~InstanceCountMixinBase() {
   base::AutoLock lock(lock_);
 
@@ skipping 27 matching lines @@
 
 InstanceSet::const_iterator InstanceCountMixinBase::begin() {
   return instances.begin();
 }
 
 InstanceSet::const_iterator InstanceCountMixinBase::end() {
   return instances.end();
 }
 
 }  // namespace testing