Extract an http_parser package from shelf.

pkg/http_parser/lib/http_parser.dart

Index: pkg/http_parser/lib/http_parser.dart
diff --git a/pkg/shelf/lib/src/util.dart b/pkg/http_parser/lib/http_parser.dart
similarity index 94%
copy from pkg/shelf/lib/src/util.dart
copy to pkg/http_parser/lib/http_parser.dart
index bf8e370804ddd81dbbdbe3f453ca760ad2372e26..3b876d09e4f0a01f29c890370c113ecb238839a1 100644
--- a/pkg/shelf/lib/src/util.dart
+++ b/pkg/http_parser/lib/http_parser.dart
@@ -2,15 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-library shelf.util;
+library http_parser;
 
-import 'dart:async';
-
-import 'package:stack_trace/stack_trace.dart';
 import 'package:string_scanner/string_scanner.dart';
 
-/// Like [Future.sync], but wraps the Future in [Chain.track] as well.
-Future syncFuture(callback()) => Chain.track(new Future.sync(callback));
+export 'src/media_type.dart';
 
 const _WEEKDAYS = const ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"];
 const _MONTHS = const ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug",
@@ -122,9 +118,9 @@ int _parseInt(StringScanner scanner, int digits) {
   scanner.expect(_digitRegExp);
   if (scanner.lastMatch[0].length != digits) {
     scanner.error("expected a $digits-digit number.");
-  } else {
-    return int.parse(scanner.lastMatch[0]);
   }
+
+  return int.parse(scanner.lastMatch[0]);
 }
 
 /// Parses an timestamp of the form "HH:MM:SS" on a 24-hour clock.