Support metadata on patches.

sdk/lib/_internal/js_runtime/lib/developer_patch.dart

 // Copyright (c) 2015, 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.
 
 // Patch file for dart:developer library.
 
-import 'dart:_js_helper' show patch;
+import 'dart:_js_helper' show patch, ForceInline;
 import 'dart:_foreign_helper' show JS;
 
 @patch
 @ForceInline()
 bool debugger({bool when: true, String message}) {
   if (when) {
     JS('', 'debugger');
   }
   return when;
 }
@@ skipping 19 matching lines @@
 
 @patch
 ServiceExtensionHandler _lookupExtension(String method) {
   return _extensions[method];
 }
 
 @patch
 _registerExtension(String method, ServiceExtensionHandler handler) {
   _extensions[method] = handler;
 }