Skip type checks on native JavaScriptObjects

lib/runtime/_types.js

 // 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.
 
 /* This library defines the representation of runtime types.
 */
 
 dart_library.library('dart_runtime/_types', null, /* Imports */[
 ], /* Lazy Imports */[
   'dart/core',
@@ skipping 50 matching lines @@
 
   let voidR = new Void();
   exports.void = voidR;
 
   class Bottom extends TypeRep {
     toString() { return "bottom"; }
   };
   let bottomR = new Bottom();
   exports.bottom = bottomR;
 
+  class JSObject extends TypeRep {
+    toString() { return "NativeJavaScriptObject"; }
+  };
+  let jsobjectR = new JSObject();
+  exports.jsobject = jsobjectR;
+
   class AbstractFunctionType extends TypeRep {
     constructor() {
       super();
       this._stringValue = null;
     }
 
     toString() { return this.name; }
 
     get name() {
       if (this._stringValue) return this._stringValue;
@@ skipping 452 matching lines @@
     let typeArgs = classes.getGenericArgs(type);
     if (!typeArgs) return true;
     for (let t of typeArgs) {
       if (t != core.Object && t != dynamicR) return false;
     }
     return true;
   }
   exports.isGroundType = isGroundType;
 
 });