Move optional.h to webrtc/api/

webrtc/modules/congestion_controller/trendline_estimator.cc

 /*
  *  Copyright (c) 2016 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.
  */
 
 #include "webrtc/modules/congestion_controller/trendline_estimator.h"
 
 #include <algorithm>
 
+#include "webrtc/api/optional.h"
 #include "webrtc/modules/remote_bitrate_estimator/test/bwe_test_logging.h"
 #include "webrtc/rtc_base/checks.h"
-#include "webrtc/rtc_base/optional.h"
 
 namespace webrtc {
 
 namespace {
 rtc::Optional<double> LinearFitSlope(
     const std::deque<std::pair<double, double>>& points) {
   RTC_DCHECK(points.size() >= 2);
   // Compute the "center of mass".
   double sum_x = 0;
   double sum_y = 0;
@@ skipping 60 matching lines @@
     delay_hist_.pop_front();
   if (delay_hist_.size() == window_size_) {
     // Only update trendline_ if it is possible to fit a line to the data.
     trendline_ = LinearFitSlope(delay_hist_).value_or(trendline_);
   }
 
   BWE_TEST_LOGGING_PLOT(1, "trendline_slope", arrival_time_ms, trendline_);
 }
 
 }  // namespace webrtc