Patch to follow.
Created attachment 158513 [details]
This is a quick hack to quickly fix this problem in a not intrusive way.
I am going to follow up with a patch that simplifies uiSourceCode's content / working copy machinery and add a test for this particular problem (save as).
Comment on attachment 158513 [details]
Clearing flags on attachment: 158513
Committed r125668: <http://trac.webkit.org/changeset/125668>
All reviewed patches have been landed. Closing bug.