Tracking uniform ownership

This is a prerequisite change for the upcoming sample(child, matrix)
function. By itself, this CL doesn't really change anything; it just
adds an ownership tracking feature which sample(child, matrix) depends
on.

Change-Id: I98b12e5fb062a2535af367931e7a932ea9c63a59
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/281337
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
diff --git a/src/gpu/gradients/generated/GrSweepGradientLayout.cpp b/src/gpu/gradients/generated/GrSweepGradientLayout.cpp
index e246f7e..d9d354f 100644
--- a/src/gpu/gradients/generated/GrSweepGradientLayout.cpp
+++ b/src/gpu/gradients/generated/GrSweepGradientLayout.cpp
@@ -29,9 +29,10 @@
         (void)bias;
         auto scale = _outer.scale;
         (void)scale;
-        biasVar = args.fUniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType, "bias");
-        scaleVar =
-                args.fUniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType, "scale");
+        biasVar = args.fUniformHandler->addUniform(&_outer, kFragment_GrShaderFlag, kHalf_GrSLType,
+                                                   "bias");
+        scaleVar = args.fUniformHandler->addUniform(&_outer, kFragment_GrShaderFlag, kHalf_GrSLType,
+                                                    "scale");
         SkString sk_TransformedCoords2D_0 =
                 fragBuilder->ensureCoords2D(args.fTransformedCoords[0].fVaryingPoint);
         fragBuilder->codeAppendf(