Fix CanvasKit WebGPU build

Change-Id: I9639883a5d60b02a36bb32975a788149b1fa2980
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/853257
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Arman Uguray <armansito@google.com>
Reviewed-by: Kaylee Lubick <kjlubick@google.com>