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

tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate

Index: tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate b/tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate
index e79c5509b8926a082c19d71536aeb7f7acf181bb..6627f0b7080b00a325715dded4d0cbd3868c024d 100644
--- a/tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate
+++ b/tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate
@@ -57,8 +57,9 @@ $endif
    * For details about CSS selector syntax, see the
    * [CSS selector specification](http://www.w3.org/TR/css3-selectors/).
    */
-  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));
+
 
   String get innerHtml {
     final e = new Element.tag("div");
@@ -115,8 +116,7 @@ $endif
   @deprecated
   @Experimental()
   @DomName('DocumentFragment.querySelectorAll')
-  ElementList<Element> queryAll(String relativeSelectors) {
-    return querySelectorAll(relativeSelectors);
-  }
+  ElementList<Element /*=T*/> queryAll/*<T extends Element>*/(String relativeSelectors) =>
+    querySelectorAll(relativeSelectors);
 $!MEMBERS
 }