Make querySelectorAll a generic method so that checked mode behavior is consistent with existing be…

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>
     implements NodeListWrapper {
   // Raw Element.
   final Element _element;
@@ skipping 246 matching lines @@
   CssRect get marginEdge;
 $!STREAM_GETTER_SIGNATURES
 }
 
 // Wrapper over an immutable NodeList to make it implement ElementList.
 //
 // Clients are {`Document`, `DocumentFragment`}.`querySelectorAll` which are
 // declared to return `ElementList`.  This provides all the static analysis
 // benefit so there is no need for this class have a constrained type parameter.
 //
-class _FrozenElementList extends ListBase<Element>
-    implements ElementList<Element>, NodeListWrapper {
+class _FrozenElementList<E extends Element> extends ListBase<E>
+    implements ElementList<E>, NodeListWrapper {
   final List<Node> _nodeList;
 
 $if JSINTEROP
   var dartClass_instance;
 
   _FrozenElementList._wrap(this._nodeList) {
       this.dartClass_instance = this._nodeList;
   }
 $else
   _FrozenElementList._wrap(this._nodeList);
 $endif
 
   int get length => _nodeList.length;
 
-  Element operator [](int index) => _nodeList[index];
+  E operator [](int index) => _nodeList[index] as E;

[sra1, 2016/04/21 22:43:15]

E _asE(Node node) {
  E element = node;
  return element;
}

E operator [](int index) => _asE(_nodeList[index]);

 
-  void operator []=(int index, Element value) {
+  void operator []=(int index, E value) {
     throw new UnsupportedError('Cannot modify list');
   }
 
   set length(int newLength) {
     throw new UnsupportedError('Cannot modify list');
   }
 
-  void sort([Comparator<Element> compare]) {
+  void sort([Comparator<E> compare]) {
     throw new UnsupportedError('Cannot sort list');
   }
 
   void shuffle([Random random]) {
     throw new UnsupportedError('Cannot shuffle list');
   }
 
-  Element get first => _nodeList.first;
+  E get first => _nodeList.first as E;

[sra1, 2016/04/21 22:43:15]

=> _asE(_nodeList.first);

 
-  Element get last => _nodeList.last;
+  E get last => _nodeList.last as E;
 
-  Element get single => _nodeList.single;
+  E get single => _nodeList.single as E;
 
   CssClassSet get classes => new _MultiElementCssClassSet(this);
 
   CssStyleDeclarationBase get style =>
       new _CssStyleDeclarationSet(this);
 
   set classes(Iterable<String> value) {
     // TODO(sra): This might be faster for Sets:
     //
     //     new _MultiElementCssClassSet(this).writeClasses(value)
@@ skipping 288 matching lines @@
    * group of selectors.
    *
    * [selectors] should be a string using CSS selector syntax.
    *
    *     var items = element.querySelectorAll('.itemClassName');
    *
    * For details about CSS selector syntax, see the
    * [CSS selector specification](http://www.w3.org/TR/css3-selectors/).
    */
   @DomName('Element.querySelectorAll')
-  ElementList<Element> querySelectorAll(String selectors) =>
-    new _FrozenElementList._wrap(_querySelectorAll(selectors));
+  ElementList<Element /*=T*/> querySelectorAll/*<T extends Element>*/(String selectors) =>
+    new _FrozenElementList/*<T>*/._wrap(_querySelectorAll(selectors));
 
   /**
    * Alias for [querySelector]. Note this function is deprecated because its
    * semantics will be changing in the future.
    */
   @deprecated
   @DomName('Element.querySelector')
   @Experimental()
   Element query(String relativeSelectors) => querySelector(relativeSelectors);
 
   /**
    * Alias for [querySelectorAll]. Note this function is deprecated because its
    * semantics will be changing in the future.
    */
   @deprecated
   @DomName('Element.querySelectorAll')
   @Experimental()
-  ElementList<Element> queryAll(String relativeSelectors) =>
+  ElementList<Element /*=T*/> queryAll/*<T extends Element>*/(String relativeSelectors) =>
       querySelectorAll(relativeSelectors);
 
   /**
    * The set of CSS classes applied to this element.
    *
    * This set makes it easy to add, remove or toggle the classes applied to
    * this element.
    *
    *     element.classes.add('selected');
    *     element.classes.toggle('isOnline');
@@ skipping 1025 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');
 }