Convert the prototype method of context2d to v4

Change-Id: Id00238adc3ecca8f5008ee1a1015d6b25eb29d6a
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Remove debug output

Change-Id: Ic2011366d7606761f4327f1b4e92c9741a5f30ef
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>