base: Put DISALLOW_COPY_AND_ASSIGN inside private section of classes.

base/test/mock_devices_changed_observer.h

 // 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.
 
 #ifndef BASE_TEST_MOCK_DEVICES_CHANGED_OBSERVER_H_
 #define BASE_TEST_MOCK_DEVICES_CHANGED_OBSERVER_H_
 
 #include <string>
 
 #include "base/system_monitor/system_monitor.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace base {
 
 class MockDevicesChangedObserver
     : public base::SystemMonitor::DevicesChangedObserver {
  public:
   MockDevicesChangedObserver();
   ~MockDevicesChangedObserver();
 
   MOCK_METHOD1(OnDevicesChanged,
                void(base::SystemMonitor::DeviceType device_type));
 
+ private:
   DISALLOW_COPY_AND_ASSIGN(MockDevicesChangedObserver);
 };
 
 }  // namespace base
 
 #endif  // BASE_TEST_MOCK_DEVICES_CHANGED_OBSERVER_H_