Use metadata annotation @patch for patch classes

runtime/lib/uri_patch.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 import "dart:convert" show ASCII;
 
 // VM implementation of Uri.
 typedef Uri _UriBaseClosure();
 
 Uri _unsupportedUriBase() {
   throw new UnsupportedError("'Uri.base' is not supported");
 }
 
 // _uriBaseClosure can be overwritten by the embedder to supply a different
 // value for Uri.base.
 _UriBaseClosure _uriBaseClosure = _unsupportedUriBase;
 
-patch class Uri {
+@patch class Uri {
   static final bool _isWindowsCached = _isWindowsPlatform;
 
-  /* patch */ static bool get _isWindows => _isWindowsCached;
+  /* @patch */ static bool get _isWindows => _isWindowsCached;
 
-  /* patch */ static Uri get base => _uriBaseClosure();
+  /* @patch */ static Uri get base => _uriBaseClosure();
 
   static bool get _isWindowsPlatform native "Uri_isWindowsPlatform";
 
-  /* patch */ static String _uriEncode(List<int> canonicalTable,
-                                       String text,
-                                       Encoding encoding,
-                                       bool spaceToPlus) {
+  /* @patch */ static String _uriEncode(List<int> canonicalTable,
+                                        String text,
+                                        Encoding encoding,
+                                        bool spaceToPlus) {
     // First check if the text will be changed by encoding.
     int i = 0;
     if (identical(encoding, UTF8) ||
         identical(encoding, LATIN1) ||
         identical(encoding, ASCII)) {
       // Encoding is compatible with the original string.
       // Find first character that needs encoding.
       for (; i < text.length; i++) {
         var char = text.codeUnitAt(i);
         if (char >= 128 ||
@@ skipping 23 matching lines @@
       } else {
         const String hexDigits = '0123456789ABCDEF';
         result..writeCharCode(_PERCENT)
               ..writeCharCode(hexDigits.codeUnitAt(byte >> 4))
               ..writeCharCode(hexDigits.codeUnitAt(byte & 0x0f));
       }
     }
     return result.toString();
   }
 }