Don't call GrSurfaceDrawContext::setNeedsStencil until after splits

We used to call setNeedsStencil before potential opsTask splits due to
dst reads. This caused the code to assume the stencil was getting
cleared when it actually wasn't. This CL updates the code to not call
setNeedsStencil until all splits are finished.

Bug: skia:12153
Change-Id: I3eb973b77929677b2535e461948b73e93ee29111
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/428696
Auto-Submit: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
1 file changed