[graphite] Add sampleCount to pipeline key.

Without this fix, a Pipeline created for an attachment with one
sampleCount could be found and used for an attachment with a different
sampleCount, which is invalid.

Change-Id: Ibab0736e0e8dd7b920485eec54d70f00ab8507c5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/554999
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
1 file changed