WebView OnDraw function is mainly native?

[Android007]

Hi everyone,
I wanted to understand better how the webkit works.
I can see that many of the functions call native functions, however I also noticed that a Picture instance is also used (which is a pure java object that is drawn into the canvas) .
I wanted to know whether most of the graphic work is done natively, or on the Picture object.
Maybe only the history is saved as a Picture, but "live" graphics is done natively?

Any assistance would be greatly appreciated.

Thanks