Remove color space xform from alpha threshold FP

This does math on the sampled color. In order to do that math in the
destination color space, I split the behavior up - the threshold FP
now operates on the input color, and we construct a series with a
simple texture effect (possibly wrapped in a color xform), then the
threshold.

I also added a GM that verifies this behavior. All other GMs using
this effect were operating on a layer source, which is always
created in the destination color space. The new GM explicitly makes
a DAG with an image source, so the alpha threshold filter needs to
handle any color space mismatch.

Bug: skia:
Change-Id: I1ed08c99f4eed17f68176bf751677a3ae1614fe3
Reviewed-on: https://skia-review.googlesource.com/61942
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

0 files changed, 0 insertions, 0 deletions