Revert "Reland Reland "Remove use of integers for atlas indexing""

This reverts commit 0711094b9150940e8c27b0d7b2c2ad85991a74db.

Reason for revert: Seeing artifacts on Pixel 3 and iOS.

Original change's description:
> Reland Reland "Remove use of integers for atlas indexing"
> 
> Bug: skia:
> Change-Id: Ie37b3fd6c8682b2d778b1dd0bc38976e6761524e
> Reviewed-on: https://skia-review.googlesource.com/c/172142
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Jim Van Verth <jvanverth@google.com>

TBR=jvanverth@google.com,bsalomon@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: skia:
Change-Id: Iff9df856ff74eeb66bf5e37496a8361474e99491
Reviewed-on: https://skia-review.googlesource.com/c/178265
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
3 files changed