Enable the -Wundef warning for clang

webrtc/video/stream_synchronization_unittest.cc

 /*
  *  Copyright (c) 2012 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 <math.h>
 
 #include <algorithm>
 
-#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/test/gtest.h"
 #include "webrtc/video/stream_synchronization.h"
 
 namespace webrtc {
 
 // These correspond to the same constants defined in vie_sync_module.cc.
 enum { kMaxVideoDiffMs = 80 };
 enum { kMaxAudioDiffMs = 80 };
 enum { kMaxDelay = 1500 };
 
 // Test constants.
@@ skipping 528 matching lines @@
 
 TEST_F(StreamSynchronizationTest,
        BothDelayedVideoLaterVideoClockDriftWithBaseDelay) {
   int base_target_delay_ms = 2000;
   video_clock_drift_ = 1.05;
   sync_->SetTargetBufferingDelay(base_target_delay_ms);
   BothDelayedVideoLaterTest(base_target_delay_ms);
 }
 
 }  // namespace webrtc