It seems that code in PasteboardGtk.cpp is advertising uri-list and image targets when they weren't available. The clipboard callback answered the request for uri-list data by filling the GtkSelectionData object with plain text data. I will attach a patch which simply uses the new clipboard code in PasteboardHelperGtk.cpp for all clipboard operations.
Created attachment 57220 [details] Patch for this issue
Comment on attachment 57220 [details] Patch for this issue Keep rocking.
Committed r60447: <http://trac.webkit.org/changeset/60447>