Use SkCanvasAndroid functions instead of deprecated canvasMethods

See https://skia-review.googlesource.com/c/skia/+/709957 for
the moved functions.

I also replace an SkASSERT (a private macro) with an proper
Android assert.

Change-Id: If03aba5e11b7c248a694d089ad38329bb5ecffdc
1 file changed