Move optional.h to webrtc/api/

webrtc/pc/rtcstatscollector.h

 /*
  *  Copyright 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.
  */
 
 #ifndef WEBRTC_PC_RTCSTATSCOLLECTOR_H_
 #define WEBRTC_PC_RTCSTATSCOLLECTOR_H_
 
 #include <map>
 #include <memory>
 #include <set>
 #include <vector>
 
+#include "webrtc/api/optional.h"
 #include "webrtc/api/stats/rtcstats_objects.h"
 #include "webrtc/api/stats/rtcstatscollectorcallback.h"
 #include "webrtc/api/stats/rtcstatsreport.h"
 #include "webrtc/call/call.h"
 #include "webrtc/media/base/mediachannel.h"
 #include "webrtc/pc/datachannel.h"
 #include "webrtc/pc/trackmediainfomap.h"
 #include "webrtc/rtc_base/asyncinvoker.h"
-#include "webrtc/rtc_base/optional.h"
 #include "webrtc/rtc_base/refcount.h"
 #include "webrtc/rtc_base/scoped_ref_ptr.h"
 #include "webrtc/rtc_base/sigslot.h"
 #include "webrtc/rtc_base/sslidentity.h"
 #include "webrtc/rtc_base/timeutils.h"
 
 namespace cricket {
 class Candidate;
 }  // namespace cricket
 
@@ skipping 150 matching lines @@
 };
 
 const char* CandidateTypeToRTCIceCandidateTypeForTesting(
     const std::string& type);
 const char* DataStateToRTCDataChannelStateForTesting(
     DataChannelInterface::DataState state);
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_PC_RTCSTATSCOLLECTOR_H_