[dart:io] Reland: Adds Platform.localeName

runtime/bin/platform_unsupported.cc

Index: runtime/bin/platform_unsupported.cc
diff --git a/runtime/bin/platform_unsupported.cc b/runtime/bin/platform_unsupported.cc
index 64f62ef7e9bb63af52fa3daa49ef3ac67a847a93..51d4fa9cd62338634eaac83cfdf690a7b1b50d98 100644
--- a/runtime/bin/platform_unsupported.cc
+++ b/runtime/bin/platform_unsupported.cc
@@ -64,6 +64,12 @@ void FUNCTION_NAME(Platform_GetVersion)(Dart_NativeArguments args) {
       "Platform is not supported on this platform"));
 }
 
+
+void FUNCTION_NAME(Platform_LocaleName)(Dart_NativeArguments args) {
+  Dart_ThrowException(DartUtils::NewInternalError(
+      "Platform is not supported on this platform"));
+}
+
 }  // namespace bin
 }  // namespace dart