DOMImplementation.createHTMLDocument("") should append an empty Text Node to the title Element as per the steps at:
https://dom.spec.whatwg.org/#dom-domimplementation-createhtmldocument (step 6)
Firefox and Chrome follow the specification here.
Currently, WebKit relies on HTMLTitleElement.text setter which does not create a Text Node if the title is the empty string, as per:
Created attachment 269609 [details]
Comment on attachment 269609 [details]
Clearing flags on attachment: 269609
Committed r195491: <http://trac.webkit.org/changeset/195491>
All reviewed patches have been landed. Closing bug.
*** Bug 139177 has been marked as a duplicate of this bug. ***