Adding polyfill support for custom elements.

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 226 matching lines @@
    * 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
    * 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;
-$!STREAM_GETTER_SIGNATURES 
+$!STREAM_GETTER_SIGNATURES
 }
 
 // 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
 // ElementList as there are valid cases where a NodeList JavaScript object
 // contains Node objects that are not Elements.
 class _FrozenElementList<T extends Element> extends ListBase<T> implements ElementList {
   final List<Node> _nodeList;
   // The subset of _nodeList that are Elements.
   List<Element> _elementList;
@@ skipping 905 matching lines @@
     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);
   }
+
+$if DART2JS
+  @JSName('innerHTML')
+  @DomName('HTMLElement.innerHTML')
+  String get innerHtml;
+
+  void set innerHtml(String value) {
+    JS('', '#.innerHTML = #', this, value);
+    // Polyfill relies on mutation observers for upgrading, but we want it

[Jennifer Messerly, 2013/08/20 19:09:59]

Interesting that the polyfill works this way... do we have an issue or bug
number on the Polymer side we can reference?

does upgrade happen synchronously in other places, such as `new Element.tag` and
`clone`?

[blois, 2013/08/20 19:36:56]

It's synchronous in clone and document.createElement but for some reason (not
sure why), innerHTML does not upgrade- it waits for the sub-tree to be added to
the document then gets upgraded by mutation observers. It could be a polyfill
limitation.

If innerHtml is rare then we could require users explicitly upgrade if they need
synchronous behavior.

+    // immediate.
+    Platform.upgradeCustomElements(this);
+  }
+$endif
+
 $!MEMBERS
 }
 
 final _START_TAG_REGEXP = new RegExp('<(\\w+)');
 class _ElementFactoryProvider {
   static const _CUSTOM_PARENT_TAG_MAP = const {
     'body' : 'html',
     'head' : 'html',
     'caption' : 'table',
     'td': 'tr',
@@ skipping 126 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');
 }