Move optional.h to webrtc/api/

webrtc/modules/include/module_common_types.h

 /*
  *  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.
  */
 
 #ifndef WEBRTC_MODULES_INCLUDE_MODULE_COMMON_TYPES_H_
 #define WEBRTC_MODULES_INCLUDE_MODULE_COMMON_TYPES_H_
 
 #include <assert.h>
 #include <string.h>  // memcpy
 
 #include <algorithm>
 #include <limits>
 
+#include "webrtc/api/optional.h"
 #include "webrtc/api/video/video_rotation.h"
 #include "webrtc/common_types.h"
 #include "webrtc/modules/video_coding/codecs/h264/include/h264_globals.h"
 #include "webrtc/modules/video_coding/codecs/vp8/include/vp8_globals.h"
 #include "webrtc/modules/video_coding/codecs/vp9/include/vp9_globals.h"
 #include "webrtc/rtc_base/constructormagic.h"
 #include "webrtc/rtc_base/deprecation.h"
-#include "webrtc/rtc_base/optional.h"
 #include "webrtc/rtc_base/safe_conversions.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 
 struct RTPAudioHeader {
   uint8_t numEnergy;                  // number of valid entries in arrOfEnergy
   uint8_t arrOfEnergy[kRtpCsrcSize];  // one energy byte (0-9) per channel
   bool isCNG;                         // is this CNG
   size_t channel;                     // number of channels 2 = stereo
@@ skipping 600 matching lines @@
   static constexpr int kNotAProbe = -1;
   int send_bitrate_bps = -1;
   int probe_cluster_id = kNotAProbe;
   int probe_cluster_min_probes = -1;
   int probe_cluster_min_bytes = -1;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_INCLUDE_MODULE_COMMON_TYPES_H_