Revert "Dartium JS Interop enabled."

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

Index: tools/dom/templates/html/impl/impl_DocumentType.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_DocumentType.darttemplate b/tools/dom/templates/html/impl/impl_DocumentType.darttemplate
deleted file mode 100644
index 88e7e6eae0b91f64cf73887175d6ad79e4dd5177..0000000000000000000000000000000000000000
--- a/tools/dom/templates/html/impl/impl_DocumentType.darttemplate
+++ /dev/null
@@ -1,16 +0,0 @@
-// 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 $LIBRARYNAME;
-
-@DocsEditable()
-$(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
-$!MEMBERS
-$if DARTIUM
-  // Override this methods for Dartium _DocumentType can't be abstract.
-  Element get nextElementSibling => wrap_jso(_blink.BlinkDocumentType.instance.nextElementSibling_Getter_(unwrap_jso(this)));
-  Element get previousElementSibling => wrap_jso(_blink.BlinkDocumentType.instance.previousElementSibling_Getter_(unwrap_jso(this)));
-$endif
-}
-