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>

src/core/SkBlurMF.cpp

@@ -790,8 +790,8 @@ GrSurfaceProxyView SkBlurMaskFilterImpl::filterMaskGPU(GrRecordingContext* conte
             paint.setCoverageSetOpXPFactory(SkRegion::kReplace_Op);
         }
 
-        surfaceDrawContext->drawRect(nullptr, std::move(paint), GrAA::kNo, SkMatrix::I(),
-                                     SkRect::Make(clipRect));
+        surfaceDrawContext->fillPixelsWithLocalMatrix(nullptr, std::move(paint), clipRect,
+                                                      SkMatrix::I());
     }
 
     return surfaceDrawContext->readSurfaceView();