Add a method on native classes for is checks. Reduces the code for generating is checks.

frog/leg/lib/native_helper.dart

 // Copyright (c) 2012, 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.
 
 String typeNameInChrome(obj) {
   String name = JS('String', "#.constructor.name", obj);
   if (name == 'Window') return 'DOMWindow';
   return name;
 }
 
@@ skipping 239 matching lines @@
     String tag = inputTable[i][0];
     String tags = inputTable[i][1];
     Set<String> set = new Set<String>();
     List<String> tagNames = tags.split('|');
     for (int j = 0; j < tagNames.length; j++) {
       set.add(tagNames[j]);
     }
     _dynamicMetadata.add(new MetaInfo(tag, tags, set));
   }
 }
-
-// Initialized by the compiler.
-var isChecksHelper;
-
-// This method will be called for 'is' checks on native types.
-// It takes the object on which the 'is' check is being done, and the
-// property name for the type check. The method patches the real
-// prototype of the object with the value from the Dart object
-// (see [generateNativeClass]).
-bool dynamicIsCheck(obj, String typeName) {
-  if (isJsArray(obj)) return false;
-  // Check if the Dart object corresponding to this class has the property.
-  var res = JS('bool', '!!#[#][#]', isChecksHelper, getTypeNameOf(obj),
-      typeName);
-  var proto = JS('var', 'Object.getPrototypeOf(#)', obj);
-  defineProperty(proto, typeName, res);
-  return res;
-}