Fix bug where multiple JSObject wrappers could be created for the same JsObject.

sdk/lib/js/dartium/js_dartium.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.
 
 /**
  * Support for interoperating with JavaScript.
  *
  * This library provides access to JavaScript objects from Dart, allowing
  * Dart code to get and set properties, and call methods of JavaScript objects
  * and invoke JavaScript functions. The library takes care of converting
@@ skipping 654 matching lines @@
 }
 
 // Interfaces that are safe to slam on all DOM classes.
 // Adding implementsClause would be risky as it could contain Function which
 // is likely to break a lot of instanceof checks.
 abstract class JSObjectInterfacesDom $implementsClauseDom {
 }
 
 patch class JSObject {
   factory JSObject.create(JsObject jsObject) {
-    return new JSObjectImpl.internal()..blink_jsObject = jsObject;
+    var ret = new JSObjectImpl.internal()..blink_jsObject = jsObject;
+    jsObject._dartHtmlWrapper = ret;
+    return ret;
   }
 }
 
 patch class JSFunction {
   factory JSFunction.create(JsObject jsObject) {
-    return new JSFunctionImpl.internal()..blink_jsObject = jsObject;
+    var ret = new JSFunctionImpl.internal()..blink_jsObject = jsObject;
+    jsObject._dartHtmlWrapper = ret;
+    return ret;
   }
 }
 
 patch class JSArray {
   factory JSArray.create(JsObject jsObject) {
-    return new JSArrayImpl.internal()..blink_jsObject = jsObject;
+    var ret = new JSArrayImpl.internal()..blink_jsObject = jsObject;
+    jsObject._dartHtmlWrapper = ret;
+    return ret;
   }
 }
 
 _registerAllJsInterfaces() {
   _registerJsInterfaces([${allTypes.join(", ")}]);
 }
 
 ''');
   ret..addAll(["dart:js", "JSInteropImpl.dart", sb.toString()]);
   return ret;
@@ skipping 856 matching lines @@
     var ret = _interopCaptureThisExpando[f];
     if (ret == null) {
       // TODO(jacobr): we could optimize this.
       ret = new JSFunction.create(
           new JsFunction.withThis(new _CreateDartFunctionForInterop(f)));
       _interopCaptureThisExpando[f] = ret;
     }
     return ret;
   }
 }