Comment 4 for bug 1274315

So, from what I gather:

* The QImage is non-null because QPainter::drawImage skips null images.
* The Qt paint engine in use is QGL2PaintEngineEx
* OpenGL context sharing seems to have been setup successfully:

Debug [Main]: Set root GL Context widget valid: QGLWidget(0x9a41760) true
Debug [Main]: Created root GL Context valid: 0x9a41990 true
Debug [Main]: Root GL Context format:
Debug [Main]: Double Buffering: true
Debug [Main]: Swap interval: 0
Debug [Main]: Depth buffer: true
Debug [Main]: Direct rendering: true
Debug [Main]: Has overlay: false
Debug [Main]: RGBA: true
Debug [Main]: Sample buffers: false
Debug [Main]: Stencil buffers: true
Debug [Main]: Stereo: false