Override Date.prototype.to*String with Intl.DateTimeFormat.format

src/runtime/runtime-i18n.cc

Index: src/runtime/runtime-i18n.cc
diff --git a/src/runtime/runtime-i18n.cc b/src/runtime/runtime-i18n.cc
index afa9cc849fe78b8678d022b5c62fde4434ea437b..f7dbe8a462d0e999d87613cbcfa26d23d69a9a8e 100644
--- a/src/runtime/runtime-i18n.cc
+++ b/src/runtime/runtime-i18n.cc
@@ -471,6 +471,27 @@ bool AddElement(Handle<JSArray> array, int index, int32_t field_id,
   return true;
 }
 
+#if 0
+RUNTIME_FUNCTION(Runtime_UpdateTimezoneInDateFormat) {
+  HandleScope scope(isolate);
+
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(JSObject, date_format_holder, 0);
+
+  // TODO(jshin): Updating the timezone of |date_format| everytime cached
+  // DateFormat is used is not optimal. date_format_holder can be
+  // changed to store DATE_CACHE_VERSION and update the timezone in
+  // |date_format| only when the stored DATE_CACHE_VERSION is different from
+  // the current DATE_CACHE_VERSION.
+  icu::SimpleDateFormat* date_format =
+      DateFormat::UnpackDateFormat(isolate, date_format_holder);
+  if (!date_format) return isolate->ThrowIllegalOperation();
+
+  date_format->adoptTimeZone(icu::TimeZone::createDefault());
+  return isolate->heap()->true_value();
+}
+#endif
+
 }  // namespace
 
 RUNTIME_FUNCTION(Runtime_InternalDateFormatToParts) {