Move optional.h to webrtc/api/

webrtc/api/BUILD.gn

 # Copyright (c) 2015 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.
 
 import("../webrtc.gni")
 if (is_android) {
@@ skipping 189 matching lines @@
 
 rtc_source_set("array_view") {
   sources = [
     "array_view.h",
   ]
   deps = [
     "../rtc_base:rtc_base_approved",
   ]
 }
 
+rtc_source_set("optional") {
+  sources = [
+    "optional.cc",
+    "optional.h",
+  ]
+  deps = [
+    ":array_view",
+    "../rtc_base:rtc_base_approved",
+  ]
+}
+
 rtc_source_set("libjingle_peerconnection_test_api") {
   testonly = true
   sources = [
     "test/fakeconstraints.h",
   ]
 
   public_deps = [
     ":libjingle_peerconnection_api",
   ]
 
@@ skipping 39 matching lines @@
     testonly = true
 
     # Skip restricting visibility on mobile platforms since the tests on those
     # gets additional generated targets which would require many lines here to
     # cover (which would be confusing to read and hard to maintain).
     if (!is_android && !is_ios) {
       visibility = [ "..:rtc_unittests" ]
     }
     sources = [
       "array_view_unittest.cc",
+      "optional_unittest.cc",
       "ortc/mediadescription_unittest.cc",
       "ortc/sessiondescription_unittest.cc",
       "rtcerror_unittest.cc",
       "rtpparameters_unittest.cc",
     ]
 
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
 
     deps = [
       ":array_view",
       ":libjingle_peerconnection_api",
+      ":optional",
       ":ortc_api",
       "../rtc_base:rtc_base_approved",
       "../rtc_base:rtc_base_tests_utils",
       "../test:test_support",
     ]
   }
 }