Recommit changing List.skip/take/revert returns Iterable and remove mappedBy.

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

Index: tools/dom/templates/html/impl/impl_Element.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_Element.darttemplate b/tools/dom/templates/html/impl/impl_Element.darttemplate
index 791b1ab6f76b14a6a3d9731c60b3a8e4cfaf6c67..605731c4928078663a82f59cfaa12d0c49398dc1 100644
--- a/tools/dom/templates/html/impl/impl_Element.darttemplate
+++ b/tools/dom/templates/html/impl/impl_Element.darttemplate
@@ -65,10 +65,6 @@ class _ChildrenElementList implements List {
     return IterableMixinWorkaround.mapList(this, f);
   }
 
-  List mappedBy(f(Element element)) {
-    return IterableMixinWorkaround.mappedByList(this, f);
-  }
-
   Iterable<Element> where(bool f(Element element)) {
     return IterableMixinWorkaround.where(this, f);
   }
@@ -149,7 +145,7 @@ class _ChildrenElementList implements List {
     }
   }
 
-  List<Element> get reversed {
+  Iterable<Element> get reversed {
     return IterableMixinWorkaround.reversedList(this);
   }
 
@@ -290,10 +286,6 @@ class _FrozenElementList implements List {
     return IterableMixinWorkaround.mapList(this, f);
   }
 
-  List mappedBy(f(Element element)) {
-    return IterableMixinWorkaround.mappedByList(this, f);
-  }
-
   Iterable<Element> where(bool f(Element element)) {
     return IterableMixinWorkaround.where(this, f);
   }
@@ -383,7 +375,7 @@ class _FrozenElementList implements List {
     throw new UnsupportedError('');
   }
 
-  List<Element> get reversed {
+  Iterable<Element> get reversed {
     return IterableMixinWorkaround.reversedList(this);
   }