Revert "Revert "Make stdout/stderr async""

runtime/bin/stdio.cc

Index: runtime/bin/stdio.cc
diff --git a/runtime/bin/stdio.cc b/runtime/bin/stdio.cc
index 2ed93fb51a3d800013f9f6552023ac59e0b4035d..ab3b8a2f4489c439165fda7423a48a9f7bb34454 100644
--- a/runtime/bin/stdio.cc
+++ b/runtime/bin/stdio.cc
@@ -45,13 +45,8 @@ void FUNCTION_NAME(Stdin_SetLineMode)(Dart_NativeArguments args) {
 
 
 void FUNCTION_NAME(Stdout_GetTerminalSize)(Dart_NativeArguments args) {
-  intptr_t fd = DartUtils::GetIntptrValue(Dart_GetNativeArgument(args, 0));
-  if (fd != 1 && fd != 2) {
-    Dart_PropagateError(Dart_NewApiError("Terminal fd must be 1 or 2"));
-  }
-
   int size[2];
-  if (Stdout::GetTerminalSize(fd, size)) {
+  if (Stdout::GetTerminalSize(size)) {
     Dart_Handle list = Dart_NewList(2);
     Dart_ListSetAt(list, 0, Dart_NewInteger(size[0]));
     Dart_ListSetAt(list, 1, Dart_NewInteger(size[1]));