remove bindModel, the same effect can be achieved through createInstance

tools/dom/templates/html/impl/impl_Element.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.
 
 part of $LIBRARYNAME;
 
 class _ChildrenElementList extends ListBase<Element> {
   // Raw Element.
   final Element _element;
   final HtmlCollection _childElements;
@@ skipping 139 matching lines @@
   }
 
   Element get single {
     if (length > 1) throw new StateError("More than one element");
     return first;
   }
 }
 
 /**
  * An immutable list containing HTML elements. This list contains some
- * additional methods when compared to regular lists for ease of CSS 
+ * additional methods when compared to regular lists for ease of CSS
  * manipulation on a group of elements.
  */
 abstract class ElementList<T extends Element> extends ListBase<T> {
   /**
    * The union of all CSS classes applied to the elements in this list.
    *
    * This set makes it easy to add, remove or toggle (add if not present, remove
    * if present) the classes applied to a collection of elements.
    *
    *     htmlList.classes.add('selected');
@@ skipping 10 matching lines @@
    * [ElementList].
    *
    * Grouping the style objects all together provides easy editing of specific
    * properties of a collection of elements. Setting a specific property value
    * will set that property in all [Element]s in the [ElementList]. Getting a
    * specific property value will return the value of the property of the first
    * element in the [ElementList].
    */
   CssStyleDeclarationBase get style;
 
-  /** 
+  /**
    * Access dimensions and position of the Elements in this list.
-   * 
+   *
    * Setting the height or width properties will set the height or width
-   * property for all elements in the list. This returns a rectangle with the 
+   * property for all elements in the list. This returns a rectangle with the
    * dimenions actually available for content
-   * in this element, in pixels, regardless of this element's box-sizing 
+   * in this element, in pixels, regardless of this element's box-sizing
    * property. Getting the height or width returns the height or width of the
-   * first Element in this list. 
+   * first Element in this list.
    *
    * Unlike [getBoundingClientRect], the dimensions of this rectangle
    * will return the same numerical height if the element is hidden or not.
    */
   @Experimental()
   CssRect get contentEdge;
-  
+
   /**
    * Access dimensions and position of the first Element's content + padding box
    * in this list.
-   * 
+   *
    * This returns a rectangle with the dimenions actually available for content
-   * in this element, in pixels, regardless of this element's box-sizing 
+   * in this element, in pixels, regardless of this element's box-sizing
    * property. Unlike [getBoundingClientRect], the dimensions of this rectangle
    * will return the same numerical height if the element is hidden or not. This
    * can be used to retrieve jQuery's `innerHeight` value for an element. This
    * is also a rectangle equalling the dimensions of clientHeight and
    * clientWidth.
    */
   @Experimental()
   CssRect get paddingEdge;
 
   /**
    * Access dimensions and position of the first Element's content + padding +
    * border box in this list.
-   * 
+   *
    * This returns a rectangle with the dimenions actually available for content
-   * in this element, in pixels, regardless of this element's box-sizing 
+   * in this element, in pixels, regardless of this element's box-sizing
    * property. Unlike [getBoundingClientRect], the dimensions of this rectangle
    * will return the same numerical height if the element is hidden or not. This
    * can be used to retrieve jQuery's `outerHeight` value for an element.
    */
   @Experimental()
   CssRect get borderEdge;
 
   /**
    * Access dimensions and position of the first Element's content + padding +
    * border + margin box in this list.
-   * 
+   *
    * This returns a rectangle with the dimenions actually available for content
-   * in this element, in pixels, regardless of this element's box-sizing 
+   * in this element, in pixels, regardless of this element's box-sizing
    * property. Unlike [getBoundingClientRect], the dimensions of this rectangle
    * will return the same numerical height if the element is hidden or not. This
    * can be used to retrieve jQuery's `outerHeight` value for an element.
    */
   @Experimental()
   CssRect get marginEdge;
 }
 
 // TODO(jacobr): this is an inefficient implementation but it is hard to see
 // a better option given that we cannot quite force NodeList to be an
@@ skipping 24 matching lines @@
     throw new UnsupportedError('Cannot sort list');
   }
 
   Element get first => _nodeList.first;
 
   Element get last => _nodeList.last;
 
   Element get single => _nodeList.single;
 
   CssClassSet get classes => new _MultiElementCssClassSet(_elementList);
-  
-  CssStyleDeclarationBase get style => 
+
+  CssStyleDeclarationBase get style =>
       new _CssStyleDeclarationSet(_elementList);
 
   void set classes(Iterable<String> value) {
     _elementList.forEach((e) => e.classes = value);
   }
 
   CssRect get contentEdge => new _ContentCssListRect(_elementList);
-  
+
   CssRect get paddingEdge => _elementList.first.paddingEdge;
 
   CssRect get borderEdge => _elementList.first.borderEdge;
 
   CssRect get marginEdge => _elementList.first.marginEdge;
 }
 
 /**
  * An abstract class, which all HTML elements extend.
  */
@@ skipping 640 matching lines @@
    * Gets the content of this template.
    * This is only supported if [isTemplate] is true.
    */
   @Experimental()
   DocumentFragment get content {
     _ensureTemplate();
     return _templateContent;
   }
 
   /**
-   * Creates an instance of the template, using the provided model and binding
-   * delegate.
+   * Creates an instance of the template, using the provided model and optional
+   * binding delegate.
    *
    * This is only supported if [isTemplate] is true.
    */
   @Experimental()
-  DocumentFragment createInstance(model, BindingDelegate delegate) {
+  DocumentFragment createInstance(model, [BindingDelegate delegate]) {

[Jennifer Messerly, 2013/07/31 02:47:02]

it's not always easy to tell which things are intended to be optional from the
JS code, but this one was apparent from trying to use it. Why make me pass a
null BindingDelegate? :)

     _ensureTemplate();
     return TemplateElement.mdvPackage(this).createInstance(model, delegate);
   }
 
   /**
    * The data model which is inherited through the tree.
    * This is only supported if [isTemplate] is true.
    */
   @Experimental()
   get model => TemplateElement.mdvPackage(this).model;
@@ skipping 55 matching lines @@
 
   void _ensureTemplate() {
     if (!isTemplate) {
       throw new UnsupportedError('$this is not a template.');
     }
     TemplateElement.decorate(this);
   }
 
   /**
    * Access this element's content position.
-   * 
+   *
    * This returns a rectangle with the dimenions actually available for content
-   * in this element, in pixels, regardless of this element's box-sizing 
+   * in this element, in pixels, regardless of this element's box-sizing
    * property. Unlike [getBoundingClientRect], the dimensions of this rectangle
    * will return the same numerical height if the element is hidden or not.
-   * 
+   *
    * _Important_ _note_: use of this method _will_ perform CSS calculations that
-   * can trigger a browser reflow. Therefore, use of this property _during_ an 
-   * animation frame is discouraged. See also: 
+   * can trigger a browser reflow. Therefore, use of this property _during_ an
+   * animation frame is discouraged. See also:
    * [Browser Reflow](https://developers.google.com/speed/articles/reflow)
    */
   @Experimental()
   CssRect get contentEdge => new _ContentCssRect(this);
-  
+
   /**
    * Access the dimensions and position of this element's content + padding box.
-   * 
+   *
    * This returns a rectangle with the dimenions actually available for content
-   * in this element, in pixels, regardless of this element's box-sizing 
+   * in this element, in pixels, regardless of this element's box-sizing
    * property. Unlike [getBoundingClientRect], the dimensions of this rectangle
    * will return the same numerical height if the element is hidden or not. This
    * can be used to retrieve jQuery's
-   * [innerHeight](http://api.jquery.com/innerHeight/) value for an element. 
+   * [innerHeight](http://api.jquery.com/innerHeight/) value for an element.
    * This is also a rectangle equalling the dimensions of clientHeight and
    * clientWidth.
-   * 
+   *
    * _Important_ _note_: use of this method _will_ perform CSS calculations that
-   * can trigger a browser reflow. Therefore, use of this property _during_ an 
-   * animation frame is discouraged. See also: 
+   * can trigger a browser reflow. Therefore, use of this property _during_ an
+   * animation frame is discouraged. See also:
    * [Browser Reflow](https://developers.google.com/speed/articles/reflow)
    */
   @Experimental()
   CssRect get paddingEdge => new _PaddingCssRect(this);
 
   /**
    * Access the dimensions and position of this element's content + padding +
    * border box.
-   * 
+   *
    * This returns a rectangle with the dimenions actually available for content
-   * in this element, in pixels, regardless of this element's box-sizing 
+   * in this element, in pixels, regardless of this element's box-sizing
    * property. Unlike [getBoundingClientRect], the dimensions of this rectangle
    * will return the same numerical height if the element is hidden or not. This
    * can be used to retrieve jQuery's
    * [outerHeight](http://api.jquery.com/outerHeight/) value for an element.
-   * 
-   * _Important_ _note_: use of this method _will_ perform CSS calculations that 
-   * can trigger a browser reflow. Therefore, use of this property _during_ an 
-   * animation frame is discouraged. See also: 
+   *
+   * _Important_ _note_: use of this method _will_ perform CSS calculations that
+   * can trigger a browser reflow. Therefore, use of this property _during_ an
+   * animation frame is discouraged. See also:
    * [Browser Reflow](https://developers.google.com/speed/articles/reflow)
    */
   @Experimental()
   CssRect get borderEdge => new _BorderCssRect(this);
 
   /**
    * Access the dimensions and position of this element's content + padding +
    * border + margin box.
-   * 
+   *
    * This returns a rectangle with the dimenions actually available for content
-   * in this element, in pixels, regardless of this element's box-sizing 
+   * in this element, in pixels, regardless of this element's box-sizing
    * property. Unlike [getBoundingClientRect], the dimensions of this rectangle
    * will return the same numerical height if the element is hidden or not. This
    * can be used to retrieve jQuery's
    * [outerHeight](http://api.jquery.com/outerHeight/) value for an element.
-   * 
+   *
    * _Important_ _note_: use of this method will perform CSS calculations that
-   * can trigger a browser reflow. Therefore, use of this property _during_ an 
-   * animation frame is discouraged. See also: 
+   * can trigger a browser reflow. Therefore, use of this property _during_ an
+   * animation frame is discouraged. See also:
    * [Browser Reflow](https://developers.google.com/speed/articles/reflow)
    */
   @Experimental()
   CssRect get marginEdge => new _MarginCssRect(this);
 
-  /** 
-   * Provides the coordinates of the element relative to the top of the 
-   * document. 
+  /**
+   * Provides the coordinates of the element relative to the top of the
+   * document.
    *
-   * This method is the Dart equivalent to jQuery's 
+   * This method is the Dart equivalent to jQuery's
    * [offset](http://api.jquery.com/offset/) method.
    */
   Point get documentOffset => offsetTo(document.documentElement);
 
-  /** 
+  /**
    * Provides the offset of this element's [borderEdge] relative to the
    * specified [parent].
-   * 
+   *
    * This is the Dart equivalent of jQuery's
    * [position](http://api.jquery.com/position/) method. Unlike jQuery's
-   * position, however, [parent] can be any parent element of `this`, 
+   * position, however, [parent] can be any parent element of `this`,
    * rather than only `this`'s immediate [offsetParent]. If the specified
    * element is _not_ an offset parent or transitive offset parent to this
    * element, an [ArgumentError] is thrown.
    */
   Point offsetTo(Element parent) {
     return Element._offsetToHelper(this, parent);
   }
 
   static Point _offsetToHelper(Element current, Element parent) {
     // We're hopping from _offsetParent_ to offsetParent (not just parent), so
-    // offsetParent, "tops out" at BODY. But people could conceivably pass in 
+    // offsetParent, "tops out" at BODY. But people could conceivably pass in
     // the document.documentElement and I want it to return an absolute offset,
     // so we have the special case checking for HTML.
     bool foundAsParent = identical(current, parent) || parent.tagName == 'HTML';
     if (current == null || identical(current, parent)) {
       if (foundAsParent) return new Point(0, 0);
       throw new ArgumentError("Specified element is not a transitive offset "
           "parent of this element.");
-    } 
+    }
     Element parentOffset = current.offsetParent;
     Point p = Element._offsetToHelper(parentOffset, parent);
     return new Point(p.x + current.offsetLeft, p.y + current.offsetTop);
   }
 $!MEMBERS
 }
 
 
 final _START_TAG_REGEXP = new RegExp('<(\\w+)');
 class _ElementFactoryProvider {
@@ skipping 131 matching lines @@
   const ScrollAlignment._internal(this._value);
   toString() => 'ScrollAlignment.$_value';
 
   /// Attempt to align the element to the top of the scrollable area.
   static const TOP = const ScrollAlignment._internal('TOP');
   /// Attempt to center the element in the scrollable area.
   static const CENTER = const ScrollAlignment._internal('CENTER');
   /// Attempt to align the element to the bottom of the scrollable area.
   static const BOTTOM = const ScrollAlignment._internal('BOTTOM');
 }