Convert the CPU path case to use prepareForDrawing

Change-Id: I5babfc7f1fa9784d81896d5c036e3b50c2af8ca0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/207760
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
1 file changed