Move optional.h to webrtc/api/

webrtc/ortc/rtpparametersconversion.h

 /*
  *  Copyright 2017 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_ORTC_RTPPARAMETERSCONVERSION_H_
 #define WEBRTC_ORTC_RTPPARAMETERSCONVERSION_H_
 
 #include <memory>
 #include <vector>
 
+#include "webrtc/api/optional.h"
 #include "webrtc/api/rtcerror.h"
 #include "webrtc/api/rtpparameters.h"
 #include "webrtc/media/base/codec.h"
 #include "webrtc/pc/mediasession.h"
-#include "webrtc/rtc_base/optional.h"
 
 namespace webrtc {
 
 // NOTE: Some functions are templated for convenience, such that template-based
 // code dealing with AudioContentDescription and VideoContentDescription can
 // use this easily. Such methods are usable with cricket::AudioCodec and
 // cricket::VideoCodec.
 
 //***************************************************************************
 // Functions for converting from new webrtc:: structures to old cricket::
@@ skipping 67 matching lines @@
 
 template <class C>
 RtpParameters ToRtpParameters(
     const std::vector<C>& cricket_codecs,
     const cricket::RtpHeaderExtensions& cricket_extensions,
     const cricket::StreamParamsVec& stream_params);
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_ORTC_RTPPARAMETERSCONVERSION_H_