Enable the -Wundef warning for clang

webrtc/api/mediastream_unittest.cc

 /*
  *  Copyright 2011 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.
  */
 
 #include <string>
 
 #include "webrtc/api/audiotrack.h"
 #include "webrtc/api/mediastream.h"
 #include "webrtc/api/videotrack.h"
 #include "webrtc/api/test/fakevideotracksource.h"
-#include "testing/gmock/include/gmock/gmock.h"
-#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/test/gmock.h"
+#include "webrtc/test/gtest.h"
 #include "webrtc/base/gunit.h"
 #include "webrtc/base/refcount.h"
 
 static const char kStreamLabel1[] = "local_stream_1";
 static const char kVideoTrackId[] = "dummy_video_cam_1";
 static const char kAudioTrackId[] = "dummy_microphone_1";
 
 using rtc::scoped_refptr;
 using ::testing::Exactly;
 
@@ skipping 116 matching lines @@
   ChangeTrack(video_track.get());
 }
 
 TEST_F(MediaStreamTest, ChangeAudioTrack) {
   scoped_refptr<webrtc::AudioTrackInterface> audio_track(
       stream_->GetAudioTracks()[0]);
   ChangeTrack(audio_track.get());
 }
 
 }  // namespace webrtc