Move DocumentXMLTreeViewer off of private script

third_party/WebKit/Source/core/xml/DocumentXMLTreeViewer.h

Index: third_party/WebKit/Source/core/xml/DocumentXMLTreeViewer.h
diff --git a/third_party/WebKit/Source/core/xml/DocumentXMLTreeViewer.h b/third_party/WebKit/Source/core/xml/DocumentXMLTreeViewer.h
new file mode 100644
index 0000000000000000000000000000000000000000..748e2baa6cb5c4a11690303886f670c719c0078e
--- /dev/null
+++ b/third_party/WebKit/Source/core/xml/DocumentXMLTreeViewer.h
@@ -0,0 +1,16 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef DocumentXMLTreeViewer_h
+#define DocumentXMLTreeViewer_h
+
+namespace blink {
+
+class Document;
+
+void transformDocumentToXMLTreeView(Document&);
+
+}  // namespace blink
+
+#endif