Convert internal SkSL to use .eval()

Also update RELEASE_NOTES to describe new syntax.

Change-Id: I2666551b98f80b61ae3a48c92a9e306cdc7242b0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/444735
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
diff --git a/src/gpu/gradients/GrGradientShader.cpp b/src/gpu/gradients/GrGradientShader.cpp
index 2d5b2cb..b3e2fc1 100644
--- a/src/gpu/gradients/GrGradientShader.cpp
+++ b/src/gpu/gradients/GrGradientShader.cpp
@@ -425,7 +425,7 @@
         uniform int layoutPreservesOpacity;  // specialized
 
         half4 main(float2 coord) {
-            half4 t = shade(gradLayout, coord);
+            half4 t = gradLayout.eval(coord);
             half4 outColor;
 
             // If t.x is below 0, use the left border color without invoking the child processor.
@@ -442,7 +442,7 @@
             } else {
                 // Always sample from (x, 0), discarding y, since the layout FP can use y as a
                 // side-channel.
-                outColor = shade(colorizer, t.x0);
+                outColor = colorizer.eval(t.x0);
             }
             if (bool(makePremul)) {
                 outColor.rgb *= outColor.a;
@@ -487,7 +487,7 @@
         uniform int useFloorAbsWorkaround;   // specialized
 
         half4 main(float2 coord) {
-            half4 t = shade(gradLayout, coord);
+            half4 t = gradLayout.eval(coord);
 
             if (!bool(layoutPreservesOpacity) && t.y < 0) {
                 // layout has rejected this fragment (rely on sksl to remove this branch if the
@@ -511,7 +511,7 @@
 
                 // Always sample from (x, 0), discarding y, since the layout FP can use y as a
                 // side-channel.
-                half4 outColor = shade(colorizer, t.x0);
+                half4 outColor = colorizer.eval(t.x0);
                 if (bool(makePremul)) {
                     outColor.rgb *= outColor.a;
                 }