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
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index 0000000000000000000000000000000000000000..88e7e6eae0b91f64cf73887175d6ad79e4dd5177
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+++ b/tools/dom/templates/html/impl/impl_DocumentType.darttemplate
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+// 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
+}
+