Allow function declarations to take (void).

This is allowed by GLSL, so we allow it too.

GLSL ES 1.0, Section 6.1: "The idiom “(void)” as a parameter list is
provided for convenience."

Change-Id: I551c505d3de518a75acd5e306f09f0f0767e43f2
Bug: skia:12025
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/411300
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
11 files changed