Missed two files that needed dart:async import.

pkg/intl/lib/date_symbol_data_http_request.dart

Index: pkg/intl/lib/date_symbol_data_http_request.dart
diff --git a/pkg/intl/lib/date_symbol_data_http_request.dart b/pkg/intl/lib/date_symbol_data_http_request.dart
index b56c990eecd93b164d44b63bcd0601dda8e0b5fd..def256585c79ba6f4fa0cc0939c4ff641230a397 100644
--- a/pkg/intl/lib/date_symbol_data_http_request.dart
+++ b/pkg/intl/lib/date_symbol_data_http_request.dart
@@ -8,8 +8,9 @@
  */
 library date_symbol_data_json;
 
-import "date_symbols.dart";
-import "src/lazy_locale_data.dart";
+import 'dart:async';
+import 'date_symbols.dart';
+import 'src/lazy_locale_data.dart';
 import 'src/date_format_internal.dart';
 import 'src/http_request_data_reader.dart';
 
@@ -39,4 +40,4 @@ Future initializeDateFormatting(String locale, String url) {
 /** Defines how new date symbol entries are created. */
 DateSymbols _createDateSymbol(Map map) {
   return new DateSymbols.deserializeFromMap(map);
-}
+}