Make html metadata follow the spec.

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 564 matching lines @@
    * The tag should be a valid HTML tag name.
    */
   static bool isTagSupported(String tag) {
     var e = _ElementFactoryProvider.createElement_tag(tag);
     return e is Element && !(e is UnknownElement);
   }
 
   /**
    * Called by the DOM when this element has been instantiated.
    */
-  @Experimental
+  @Experimental()
   void onCreated() {}
 
   // Hooks to support custom WebComponents.
 
 $if DART2JS
   @Creates('Null')  // Set from Dart code; does not instantiate a native type.
 $endif
   Element _xtag;
 
   /**
@@ skipping 10 matching lines @@
    */
   // Note: return type is `dynamic` for convenience to suppress warnings when
   // members of the component are used. The actual type is a subtype of Element.
   get xtag => _xtag != null ? _xtag : this;
 
   void set xtag(Element value) {
     _xtag = value;
   }
 
   @DomName('Element.localName')
-  @DocsEditable
+  @DocsEditable()
   String get localName => $dom_localName;
 
   @DomName('Element.namespaceUri')
-  @DocsEditable
+  @DocsEditable()
   String get namespaceUri => $dom_namespaceUri;
 
   String toString() => localName;
 
   /**
    * Scrolls this element into view.
    *
    * Only one of of the alignment options may be specified at a time.
    *
    * If no options are specified then this will attempt to scroll the minimum
@@ skipping 154 matching lines @@
         this.parentNode.insertBefore(node, this.nextNode);
         break;
       default:
         throw new ArgumentError("Invalid position ${where}");
     }
   }
 
   /**
    * Checks if this element matches the CSS selectors.
    */
-  @Experimental
+  @Experimental()
   bool matches(String selectors) {
     if (JS('bool', '!!#.matches', this)) {
       return JS('bool', '#.matches(#)', this, selectors);
     } else if (JS('bool', '!!#.webkitMatchesSelector', this)) {
       return JS('bool', '#.webkitMatchesSelector(#)', this, selectors);
     } else if (JS('bool', '!!#.mozMatchesSelector', this)) {
       return JS('bool', '#.mozMatchesSelector(#)', this, selectors);
     } else if (JS('bool', '!!#.msMatchesSelector', this)) {
       return JS('bool', '#.msMatchesSelector(#)', this, selectors);
     }
@@ skipping 13 matching lines @@
 $endif
   DocumentFragment _templateContent;
 
   bool _templateIsDecorated;
 
 
   /**
    * Gets the template this node refers to.
    * This is only supported if [isTemplate] is true.
    */
-  @Experimental
+  @Experimental()
   Element get ref {
     _ensureTemplate();
 
     Element ref = null;
     var refId = attributes['ref'];
     if (refId != null) {
       var treeScope = this;
       while (treeScope.parentNode != null) {
         treeScope = treeScope.parentNode;
       }
 
       // Note: JS code tests that getElementById is present. We can't do that
       // easily, so instead check for the types known to implement it.
       if (treeScope is Document ||
           treeScope is ShadowRoot ||
           treeScope is svg.SvgSvgElement) {
 
         ref = treeScope.getElementById(refId);
       }
     }
 
     return ref != null ? ref : _templateInstanceRef;
   }
 
   /**
    * Gets the content of this template.
    * This is only supported if [isTemplate] is true.
    */
-  @Experimental
+  @Experimental()
   DocumentFragment get content {
     _ensureTemplate();
     return _templateContent;
   }
 
   /**
    * Creates an instance of the template.
    * This is only supported if [isTemplate] is true.
    */
-  @Experimental
+  @Experimental()
   DocumentFragment createInstance() {
     _ensureTemplate();
     return TemplateElement.mdvPackage(this).createInstance();
   }
 
   /**
    * The data model which is inherited through the tree.
    * This is only supported if [isTemplate] is true.
    */
-  @Experimental
+  @Experimental()
   get model => TemplateElement.mdvPackage(this).model;
 
-  @Experimental
+  @Experimental()
   void set model(value) {
     _ensureTemplate();
     TemplateElement.mdvPackage(this).model = value;
   }
 
   // TODO(jmesserly): const set would be better
   static const _TABLE_TAGS = const {
     'caption': null,
     'col': null,
     'colgroup': null,
@@ skipping 15 matching lines @@
    * A node is a template if [tagName] is TEMPLATE, or the node has the
    * 'template' attribute and this tag supports attribute form for backwards
    * compatibility with existing HTML parsers. The nodes that can use attribute
    * form are table elments (THEAD, TBODY, TFOOT, TH, TR, TD, CAPTION, COLGROUP
    * and COL), OPTION, and OPTGROUP.
    */
   // TODO(jmesserly): this is not a public MDV API, but it seems like a useful
   // place to document which tags our polyfill considers to be templates.
   // Otherwise I'd be repeating it in several other places.
   // See if we can replace this with a TemplateMixin.
-  @Experimental
+  @Experimental()
   bool get isTemplate => tagName == 'TEMPLATE' || _isAttributeTemplate;
 
   void _ensureTemplate() {
     if (!isTemplate) {
       throw new UnsupportedError('$this is not a template.');
     }
     TemplateElement.decorate(this);
   }
 
 $!MEMBERS
@@ skipping 136 matching lines @@
   const ScrollAlignment._internal(this._value);
   toString() => 'ScrollAlignment.$_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');
 }