wrap_jso should wrap JsArray as well, not always call wrap on its contents

tools/dom/templates/html/dartium/html_dartium.darttemplate

 // 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.
 
 // DO NOT EDIT
 // Auto-generated dart:html library.
 
 /**
  * HTML elements and other resources for web-based applications that need to
  * interact with the browser and the DOM (Document Object Model).
@@ skipping 386 matching lines @@
     }
 
     // TODO(alanknight): With upgraded custom elements this causes a failure because
     // we need a new wrapper after the type changes. We could possibly invalidate this
     // if the constructor name didn't match?
     var wrapper = js.getDartHtmlWrapperFor(jsObject);
     if (wrapper != null) {
       return wrapper;
     }
 
+    if (jsObject is js.JsArray) {
+      var wrappingList = new _DartHtmlWrappingList(jsObject);
+      js.setDartHtmlWrapperFor(jsObject, wrappingList);
+      return wrappingList;
+    }
+
     // Try the most general type conversions on it.
     // TODO(alanknight): We may be able to do better. This maintains identity,
     // which is useful, but expensive. And if we nest something that only
     // this conversion handles, how does that work? e.g. a list of maps of elements.
     var converted = convertNativeToDart_SerializedScriptValue(jsObject);
     if (!identical(converted, jsObject)) {
       return converted;
     }
     var constructor = jsObject['constructor'];
     if (__interop_checks) {
@@ skipping 125 matching lines @@
   });
   return jsObject;
 }
 
 // Converts a Dart list into a JsArray. For the Dartium version only.
 convertDartToNative_List(List input) => new js.JsArray()..addAll(input);
 
 // Conversion function place holder (currently not used in dart2js or dartium).
 List convertDartToNative_StringArray(List<String> input) => input;
 
+/**
+ * Wraps a JsArray and will call wrap_jso on its entries.
+ */
+class _DartHtmlWrappingList extends ListBase {
+  _DartHtmlWrappingList(this._basicList);
+
+  final js.JsArray _basicList;
+
+  operator [](int index) => wrap_jso(_basicList[index]);
+
+  operator []=(int index, value) => _basicList[index] = unwrap_jso(value);
+
+  int get length => _basicList.length;
+  int set length(int newLength) => _basicList.length = newLength;
+}
+
 $else
 class JsoNativeFieldWrapper extends NativeFieldWrapperClass2 {}
 
 unwrap_jso(dartClass_instance) => dartClass_instance;
 wrap_jso(jsObject) => jsObject;
 make_dart_rectangle(r) => r;
 convertDartToNative_Dictionary(Map dict) => dict;
 List convertDartToNative_StringArray(List<String> input) => input;
 convertDartToNative_List(List input) => input;
 
 $endif