draw: plumb the Options through to the type-specific code.

It'll only be used by the fallback code paths, but it's easiest if all
code paths take the extra argument.

Change-Id: I09c4067df6af7c4cd270e8ffcad96d1d8af29057
Reviewed-on: https://go-review.googlesource.com/8909
Reviewed-by: Rob Pike <r@golang.org>
2 files changed