Sorry I don't know the exact version number for webkit in Qt 5.2.1.
I opened Google map and drew an editable rectangle in it, then zoomed the map in and in. When I was trying to zoom the map to the maximum zoom level, crash occurred.
Here's the output related to the crash:
QPainter::begin: Paint device returned engine == 0, type: 2
ASSERTION FAILED: m_ptr
c:\work\build\qt5_workdir\w\s\qtwebkit\Source\WTF\wtf/OwnPtr.h(72) : WTF::OwnPtr<class WebCore::ImageBuffer>::operator ->
And the call stack is in the attachment. It seems that the "m_image" in the BitmapTextureImageBuffer class is a null empty.
Created attachment 228688 [details]
call stack when the crash occurred.