Using the function toImageData() with qtwebkit bridge in javascript crashes the program

Trying to display an image from qt (QImage) in a canvas following this guide results in a segfault: http://qt-project.org/doc/qt-5/qtwebkit-bridge.html#pixmaps-and-images

Here is the backtrace:
http://paste.kde.org/pphfjeelz

I've attached a test program.