remove mention of SkPaintDefaults_Flags

Change-Id: I0294bf2e294761bccf2e05dbd55addb003538cd1
Reviewed-on: https://skia-review.googlesource.com/c/193361
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
6 files changed