Use fillPixelsWithLocalMatrix in SkBlurMaskFilterImpl::filterMaskGPU

Use fillPixelsWithLocalMatrix instead of drawRect.

Bug: skia:11396
Change-Id: Ibaf64a5c482747d78aa5905f9e561358adcb42f2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/396556
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
1 file changed