Move optional.h to webrtc/api/

webrtc/modules/audio_processing/beamformer/array_util.h

 /*
  *  Copyright (c) 2015 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_PROCESSING_BEAMFORMER_ARRAY_UTIL_H_
 #define WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_ARRAY_UTIL_H_
 
 #include <cmath>
 #include <vector>
 
-#include "webrtc/rtc_base/optional.h"
+#include "webrtc/api/optional.h"
 
 namespace webrtc {
 
 // Coordinates in meters. The convention used is:
 // x: the horizontal dimension, with positive to the right from the camera's
 //    perspective.
 // y: the depth dimension, with positive forward from the camera's
 //    perspective.
 // z: the vertical dimension, with positive upwards.
 template<typename T>
@@ skipping 80 matching lines @@
 }
 
 template <typename T>
 T RadiansToDegrees(T angle_radians) {
   return 180 * angle_radians / M_PI;
 }
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_ARRAY_UTIL_H_