Reland of move all reference to carbon api

webrtc/base/BUILD.gn

Index: webrtc/base/BUILD.gn
diff --git a/webrtc/base/BUILD.gn b/webrtc/base/BUILD.gn
index a91b615c116a9bf7366060a783cdb6c57a957112..fe63d2076f05192ae31178851e90d8848e05d23b 100644
--- a/webrtc/base/BUILD.gn
+++ b/webrtc/base/BUILD.gn
@@ -65,9 +65,6 @@ config("rtc_base_all_dependent_config") {
       "Security.framework",
       "SystemConfiguration.framework",
     ]
-    if (current_cpu == "x86") {
-      libs += [ "Carbon.framework" ]
-    }
   }
 }
 
@@ -291,6 +288,7 @@ rtc_static_library("rtc_base") {
   defines = [ "LOGGING=1" ]
 
   sources = [
+    "applefilesystem.mm",
     "arraysize.h",
     "asyncfile.cc",
     "asyncfile.h",
@@ -339,7 +337,6 @@ rtc_static_library("rtc_base") {
     "httpcommon.h",
     "httprequest.cc",
     "httprequest.h",
-    "iosfilesystem.mm",
     "ipaddress.cc",
     "ipaddress.h",
     "linked_ptr.h",
@@ -669,10 +666,6 @@ rtc_static_library("rtc_base") {
     }
   }
 
-  if (is_ios || (is_mac && current_cpu != "x86")) {
-    defines += [ "CARBON_DEPRECATED=YES" ]
-  }
-
   if (is_linux || is_android) {
     sources += [
       "linux.cc",