Move optional.h to webrtc/api/

webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter.h

 /*
  *  Copyright (c) 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_MODULES_REMOTE_BITRATE_ESTIMATOR_TEST_ESTIMATORS_MIN_RTT_FILTER_H_
 #define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_TEST_ESTIMATORS_MIN_RTT_FILTER_H_
 
 #include <cstdint>
 #include <limits>
 #include <list>
 
-#include "webrtc/rtc_base/optional.h"
+#include "webrtc/api/optional.h"
 
 namespace webrtc {
 namespace testing {
 namespace bwe {
 
 // Average rtt for past |kRttFilterSize| packets should grow by
 // |kRttIncreaseThresholdForExpiry| in order to enter PROBE_RTT mode and expire.
 // old min_rtt estimate.
 const float kRttIncreaseThresholdForExpiry = 2.3f;
 const size_t kRttFilterSize = 25;
@@ skipping 34 matching lines @@
 
  private:
   rtc::Optional<int64_t> min_rtt_ms_;
   std::list<int64_t> rtt_samples_;
 };
 }  // namespace bwe
 }  // namespace testing
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_TEST_ESTIMATORS_MIN_RTT_FILTER_H_