Move optional.h to webrtc/api/

webrtc/rtc_base/optional.cc

Index: webrtc/rtc_base/optional.cc
diff --git a/webrtc/rtc_base/optional.cc b/webrtc/rtc_base/optional.cc
deleted file mode 100644
index 4b41a2d7fb702406ca8a0e50b8f7f2b713c80bae..0000000000000000000000000000000000000000
--- a/webrtc/rtc_base/optional.cc
+++ /dev/null
@@ -1,23 +0,0 @@
-/*
- *  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.
- */
-
-#include "webrtc/rtc_base/optional.h"
-
-namespace rtc {
-namespace optional_internal {
-
-#if RTC_HAS_ASAN
-
-void* FunctionThatDoesNothingImpl(void* x) { return x; }
-
-#endif
-
-}  // namespace optional_internal
-}  // namespace rtc