Only enlarge bounds for color filters that affect transparent black

Change-Id: I695ee063d700bea1956290d12ddfa7e0792ff894
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/432258
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
1 file changed