Revert of Remove all reference to carbon api

webrtc/BUILD.gn

Index: webrtc/BUILD.gn
diff --git a/webrtc/BUILD.gn b/webrtc/BUILD.gn
index b76cb7c07f99006d5e1201d8ca7fcdd61312dd43..1f7f52104a87f1fc805f0bd69a0a07108e3eb315 100644
--- a/webrtc/BUILD.gn
+++ b/webrtc/BUILD.gn
@@ -574,6 +574,10 @@
         "base/sslstreamadapter_unittest.cc",
       ]
     }
+    if (is_ios || (is_mac && target_cpu != "x86")) {
+      defines = [ "CARBON_DEPRECATED=YES" ]
+    }
+
     if (rtc_use_quic) {
       sources += [
         "p2p/quic/quicconnectionhelper_unittest.cc",
@@ -853,6 +857,9 @@
     if (is_mac) {
       sources += [ "base/macsocketserver_unittest.cc" ]
     }
+    if (is_ios || (is_mac && target_cpu != "x86")) {
+      defines = [ "CARBON_DEPRECATED=YES" ]
+    }
     if (is_clang) {
       # Suppress warnings from the Chromium Clang plugin.
       # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.