Move optional.h to webrtc/api/

webrtc/modules/rtp_rtcp/mocks/mock_rtp_rtcp.h

 /*
  *  Copyright (c) 2012 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_RTP_RTCP_MOCKS_MOCK_RTP_RTCP_H_
 #define WEBRTC_MODULES_RTP_RTCP_MOCKS_MOCK_RTP_RTCP_H_
 
 #include <set>
 #include <utility>
 #include <vector>
 
+#include "webrtc/api/optional.h"
 #include "webrtc/modules/include/module.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
 #include "webrtc/rtc_base/checks.h"
-#include "webrtc/rtc_base/optional.h"
 #include "webrtc/test/gmock.h"
 
 namespace webrtc {
 
 class MockRtpData : public RtpData {
  public:
   MOCK_METHOD3(OnReceivedPayloadData,
                int32_t(const uint8_t* payload_data,
                        size_t payload_size,
                        const WebRtcRTPHeader* rtp_header));
@@ skipping 169 matching lines @@
  private:
   // Mocking this method is currently not required and having a default
   // implementation like MOCK_METHOD0(TimeUntilNextProcess, int64_t())
   // can be dangerous since it can cause a tight loop on a process thread.
   virtual int64_t TimeUntilNextProcess() { return 0xffffffff; }
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_RTP_RTCP_MOCKS_MOCK_RTP_RTCP_H_