JavaScript code executed by webkit cannot call into QML declared methods, as it does not check for dynamic meta objects. The attached patch addresses this.
Created attachment 55775 [details] Proposed patch
Created attachment 55776 [details] Example testcase
Committed r59460: <http://trac.webkit.org/changeset/59460>
Revision r59460 cherry-picked into qtwebkit-2.0 with commit 592fb4ee6db52db805a6cd24552842e1e3dd7515