[canvaskit] Fix examples with makeShaderCubic

Change-Id: I1b89fc690ca93f829181d3e4e582c2285ab95573
No-Try: true
Docs-Preview: https://skia.org/?cl=350700
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/350700
Auto-Submit: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Heather Miller <hcm@google.com>
Commit-Queue: Heather Miller <hcm@google.com>
1 file changed