Move optional.h to webrtc/api/

webrtc/api/rtpparameters.h

 /*
  *  Copyright 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_API_RTPPARAMETERS_H_
 #define WEBRTC_API_RTPPARAMETERS_H_
 
 #include <string>
 #include <unordered_map>
 #include <vector>
 
 #include "webrtc/api/mediatypes.h"
-#include "webrtc/rtc_base/optional.h"
+#include "webrtc/api/optional.h"
 
 namespace webrtc {
 
 // These structures are intended to mirror those defined by:
 // http://draft.ortc.org/#rtcrtpdictionaries*
 // Contains everything specified as of 2017 Jan 24.
 //
 // They are used when retrieving or modifying the parameters of an
 // RtpSender/RtpReceiver, or retrieving capabilities.
 //
@@ skipping 511 matching lines @@
            header_extensions == o.header_extensions &&
            encodings == o.encodings &&
            degradation_preference == o.degradation_preference;
   }
   bool operator!=(const RtpParameters& o) const { return !(*this == o); }
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_RTPPARAMETERS_H_