Add sample(child, matrix) to SkSL.

This allows fragment processors to sample their children with their
local coordinate system transformed by a matrix.

Change-Id: Ifa848bbd85b939bbc5751fec5cf8f89ee904bf39
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/282590
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
diff --git a/src/gpu/effects/generated/GrDeviceSpaceEffect.cpp b/src/gpu/effects/generated/GrDeviceSpaceEffect.cpp
index fbab6e1..be9e92c 100644
--- a/src/gpu/effects/generated/GrDeviceSpaceEffect.cpp
+++ b/src/gpu/effects/generated/GrDeviceSpaceEffect.cpp
@@ -49,8 +49,9 @@
         : INHERITED(kGrDeviceSpaceEffect_ClassID, src.optimizationFlags()), fp_index(src.fp_index) {
     {
         auto clone = src.childProcessor(fp_index).clone();
-        clone->setSampledWithExplicitCoords(
-                src.childProcessor(fp_index).isSampledWithExplicitCoords());
+        if (src.childProcessor(fp_index).isSampledWithExplicitCoords()) {
+            clone->setSampledWithExplicitCoords();
+        }
         this->registerChildProcessor(std::move(clone));
     }
 }