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/gradients/generated/GrLinearGradientLayout.cpp b/src/gpu/gradients/generated/GrLinearGradientLayout.cpp
index 15849d3..2d28b92 100644
--- a/src/gpu/gradients/generated/GrLinearGradientLayout.cpp
+++ b/src/gpu/gradients/generated/GrLinearGradientLayout.cpp
@@ -25,8 +25,8 @@
         (void)_outer;
         auto gradientMatrix = _outer.gradientMatrix;
         (void)gradientMatrix;
-        SkString sk_TransformedCoords2D_0 =
-                fragBuilder->ensureCoords2D(args.fTransformedCoords[0].fVaryingPoint);
+        SkString sk_TransformedCoords2D_0 = fragBuilder->ensureCoords2D(
+                args.fTransformedCoords[0].fVaryingPoint, _outer.sampleMatrix());
         fragBuilder->codeAppendf(
                 "half t = half(%s.x) + 9.9999997473787516e-06;\n%s = half4(t, 1.0, 0.0, 0.0);\n",
                 sk_TransformedCoords2D_0.c_str(), args.fOutputColor);