Reland "[ar] Do not refer to ARCore shim in APK merger"

This is a reland of 58e4a081ad03d83758dcbbad2fda09417baabf61

Original change's description:
> [ar] Do not refer to ARCore shim in APK merger
> 
> This hard-coding should no longer be required.
> 
> Bug: 839191
> Change-Id: Id44f0f19da6efcee90ef79ea3e241eb2a7ea5843
> Reviewed-on: https://chromium-review.googlesource.com/1147706
> Commit-Queue: Ian Vollick <vollick@chromium.org>
> Reviewed-by: Richard Coles <torne@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#577662}

Bug: 839191
Change-Id: I42c3d31c0cbe49c1fe2d68c55d0db18dcdc3381d
Reviewed-on: https://chromium-review.googlesource.com/1151567
Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578347}
2 files changed