Deprecating Element.elements for Element.children.

sdk/lib/html/templates/html/impl/impl_DocumentFragment.darttemplate

Index: sdk/lib/html/templates/html/impl/impl_DocumentFragment.darttemplate
diff --git a/sdk/lib/html/templates/html/impl/impl_DocumentFragment.darttemplate b/sdk/lib/html/templates/html/impl/impl_DocumentFragment.darttemplate
index 98185a47c1f14c9b70a6fa0d1777bbeb76d8c4b8..8d240ad52d6ceca38cd70fd1ddd13615c4ab7921 100644
--- a/sdk/lib/html/templates/html/impl/impl_DocumentFragment.darttemplate
+++ b/sdk/lib/html/templates/html/impl/impl_DocumentFragment.darttemplate
@@ -46,6 +46,20 @@ class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
     elements.addAll(copy);
   }
 
+  List<Element> _children;
+  List<Element> get children {
+    if (_children == null) {
+      _children = new FilteredElementList(this);
+    }
+    return _children;
+  }
+
+  void set children(Collection<Element> value) {
+    var children = this.children;
+    children.clear();
+    children.addAll(value);
+  }
+
   Element query(String selectors) => $dom_querySelector(selectors);
 
   List<Element> queryAll(String selectors) =>