Simplify common case for recttorect

Change-Id: I70e295a677b8cac3d578e3cd57472c833af03877
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/354336
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/src/gpu/SkGpuDevice_drawTexture.cpp b/src/gpu/SkGpuDevice_drawTexture.cpp
index 7b30284..45a9a25 100644
--- a/src/gpu/SkGpuDevice_drawTexture.cpp
+++ b/src/gpu/SkGpuDevice_drawTexture.cpp
@@ -282,7 +282,7 @@
     }
 
     if (outDstRect) {
-        srcToDst->setRectToRect(src, dst, SkMatrix::kFill_ScaleToFit);
+        *srcToDst = SkMatrix::RectToRect(src, dst);
     } else {
         srcToDst->setIdentity();
     }
@@ -677,7 +677,7 @@
 
     SkRect src = SkRect::Make(special->subset());
     SkRect dst = SkRect::MakeWH(special->width(), special->height());
-    SkMatrix srcToDst = SkMatrix::MakeRectToRect(src, dst, SkMatrix::kFill_ScaleToFit);
+    SkMatrix srcToDst = SkMatrix::RectToRect(src, dst);
 
     GrSamplerState sampler(GrSamplerState::WrapMode::kClamp, downgrade_to_filter(sampling));
     GrAA aa = paint.isAntiAlias() ? GrAA::kYes : GrAA::kNo;