Remove unused function with an incorrect assert

Bug: skia:
Change-Id: I4003085fbb1cadc4aeb2e950f1a9f44f96d03a93
Reviewed-on: https://skia-review.googlesource.com/50240
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2 files changed