Revert "Remove temporary headers in //ios/web/public."

This reverts commit 32e94a7933fce1bf7c0c5b1945118855edfa0241.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Remove temporary headers in //ios/web/public.
> 
> This CL removes the temporary headers in //ios/web/public. Real headers
> are already moved into //ios/web/public/thread, and these temporary
> headers are kept to not break downstream.
> 
> Bug: 942244
> Change-Id: Ib8fe8a69c60c17125cb580180b622e5586d7eb3f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1660563
> Reviewed-by: Rohit Rao <rohitrao@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#669217}

TBR=rohitrao@chromium.org,mrsuyi@chromium.org

Change-Id: I5a8c0abd19baf75f4f5ff233ee52b6d9d54a469b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 942244
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1660504
Reviewed-by: Yi Su <mrsuyi@chromium.org>
Commit-Queue: Yi Su <mrsuyi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#669222}
4 files changed