Revert "Revert "Add integer texture support.""

This reverts commit 9c7edb8311409a141b0dc1d5e480c68c629f1997.

Fixes ASAN errors

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4736

Change-Id: I1b1dae754d357b01da7169c8e7c59d7d8d8a10f6
Reviewed-on: https://skia-review.googlesource.com/4736
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
25 files changed