Morph the APIs for Node, ParentNode, and Element closer to the specs

sky/engine/core/core.gni

Index: sky/engine/core/core.gni
diff --git a/sky/engine/core/core.gni b/sky/engine/core/core.gni
index 24d23bddb9446eb5def11e0f31ecf224b034f41f..6f2a740fbeefca6de9e67cc01abd390d6a610e7a 100644
--- a/sky/engine/core/core.gni
+++ b/sky/engine/core/core.gni
@@ -338,7 +338,6 @@ sky_core_files = [
   "dom/CharacterData.h",
   "dom/ChildListMutationScope.cpp",
   "dom/ChildListMutationScope.h",
-  "dom/ChildNode.h",
   "dom/ClientRect.cpp",
   "dom/ClientRect.h",
   "dom/ClientRectList.cpp",
@@ -458,7 +457,6 @@ sky_core_files = [
   "dom/NodeTraversal.cpp",
   "dom/NodeTraversal.h",
   "dom/NodeWithIndex.h",
-  "dom/ParentNode.h",
   "dom/Position.cpp",
   "dom/Position.h",
   "dom/PositionIterator.cpp",
@@ -1195,6 +1193,7 @@ core_idl_files = get_path_info([
                                  "dom/MutationRecord.idl",
                                  "dom/Node.idl",
                                  "dom/NodeList.idl",
+                                 "dom/ParentNode.idl",
                                  "dom/Range.idl",
                                  "dom/RequestAnimationFrameCallback.idl",
                                  "dom/shadow/ShadowRoot.idl",
@@ -1288,8 +1287,6 @@ core_dependency_idl_files =
                     "animation/DocumentAnimation.idl",
                     "animation/ElementAnimation.idl",
                     "css/DocumentFontFaceSet.idl",
-                    "dom/ChildNode.idl",
-                    "dom/ParentNode.idl",
                     "dom/URLUtils.idl",
                     "dom/URLUtilsReadOnly.idl",
                     "events/EventListener.idl",