Transform XML tree viewer to blink-in-js implementation.

This CL moves the XML tree viewer to use blink-in-js implementation. As part of this CL
the XMLTreeViewer.idl exposes transformDocumentToTreeView which is used by XMLDocumentParser
to transform into tree view.

This CL should follow up with the removal of Source/core/xml/XMLViewer.[css/js] and the subsequent
changes in public/blink_resources.grd.

BUG=341031

Review URL: https://codereview.chromium.org/479753003

git-svn-id: svn://svn.chromium.org/blink/trunk@181328 bbb929c8-8fbe-4397-9dbb-9b2b20218538