start to change Viewer's filtering to know about fonts

Did not hook-up all of the font flags, but these did not appear to be
"filtered" by viewer, so landing this version for now (to stop assuming
that text-fields are in paint).

Bug: skia:
Change-Id: Id8bdfc12f838b6c3ddc2981aca698d4d80a4c639
Reviewed-on: https://skia-review.googlesource.com/c/181169
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
2 files changed