Enable the -Wundef warning for clang

webrtc/modules/audio_coding/audio_network_adaptor/mock/mock_controller_manager.h

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_MOCK_MOCK_CONTROLLER_MANAGER_H_
 #define WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_MOCK_MOCK_CONTROLLER_MANAGER_H_
 
 #include <memory>
 #include <vector>
 
 #include "webrtc/modules/audio_coding/audio_network_adaptor/controller_manager.h"
-#include "testing/gmock/include/gmock/gmock.h"
+#include "webrtc/test/gmock.h"
 
 namespace webrtc {
 
 class MockControllerManager : public ControllerManager {
  public:
   virtual ~MockControllerManager() { Die(); }
   MOCK_METHOD0(Die, void());
   MOCK_METHOD1(
       GetSortedControllers,
       std::vector<Controller*>(const Controller::NetworkMetrics& metrics));
   MOCK_CONST_METHOD0(GetControllers, std::vector<Controller*>());
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_MOCK_MOCK_CONTROLLER_MANAGER_H_