Add Event delegation to Elements and groups of 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 
 }
 
 // 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 33 matching lines @@
     _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;
+$!ELEMENT_STREAM_GETTERS
 }
 
 /**
  * An abstract class, which all HTML elements extend.
  */
 $(ANNOTATIONS)abstract class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
   /**
    * Creates an HTML element from a valid fragment of HTML.
    *
@@ skipping 558 matching lines @@
       case 'afterend':
         this.parentNode.insertBefore(node, this.nextNode);
         break;
       default:
         throw new ArgumentError("Invalid position ${where}");
     }
   }
 
   /**
    * Checks if this element matches the CSS selectors.
+   *
+   * If `includeAncestors` is true, we examine all of this element's parent
+   * elements and also return true if any of its parent elements matches
+   * `selectors`.
    */
   @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);
-    }
-    throw new UnsupportedError("Not supported on this platform");
+  bool matches(String selectors, [includeAncestors = false]) {
+    var elem = this;
+    do {
+      bool matches = false;
+      if (JS('bool', '!!#.matches', elem)) {
+        matches = JS('bool', '#.matches(#)', elem, selectors);
+      } else if (JS('bool', '!!#.webkitMatchesSelector', elem)) {
+        matches = JS('bool', '#.webkitMatchesSelector(#)', elem, selectors);
+      } else if (JS('bool', '!!#.mozMatchesSelector', elem)) {
+        matches = JS('bool', '#.mozMatchesSelector(#)', elem, selectors);
+      } else if (JS('bool', '!!#.msMatchesSelector', elem)) {
+        matches = JS('bool', '#.msMatchesSelector(#)', elem, selectors);
+      } else {
+        throw new UnsupportedError("Not supported on this platform");
+      }
+      if (matches) return true;
+      elem = elem.parent;
+    } while(includeAncestors && elem != null);
+    return false;
   }
 $else
 $endif
 
 $if DART2JS
   @Creates('Null')  // Set from Dart code; does not instantiate a native type.
 $endif
   Element _templateInstanceRef;
 
   // Note: only used if `this is! TemplateElement`
@@ skipping 251 matching lines @@
       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 {
   static const _CUSTOM_PARENT_TAG_MAP = const {
     'body' : 'html',
     'head' : 'html',
     'caption' : 'table',
     'td': 'tr',
     'th': 'tr',
     'colgroup': 'table',
     'col' : 'colgroup',
@@ skipping 123 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');
 }