Revert "Reland: Android: Replace ConcurrentHashMap usage with manual lock."

This reverts commit b7225829975f5a97b986f51cd4c2df74bd237271.

Reason for revert: bug 921945

Original change's description:
> Reland: Android: Replace ConcurrentHashMap usage with manual lock.
> 
> ConcurrentHashMap has a bug on L.
> * Also adds a checkstyle check to prevent future uses.
> * Also adds @AnyThread / @MainThread to all public methods
> 
> Reason for reland:
>  * Now synchronizing map iterators
> 
> Bug: 905903
> Change-Id: Id7788a4707329a5e441cc010e1fb297668510aef
> Reviewed-on: https://chromium-review.googlesource.com/c/1409725
> Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
> Commit-Queue: agrieve <agrieve@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#622699}

TBR=agrieve@chromium.org,tiborg@chromium.org

Change-Id: Ifa376b028ffe8d08517a87145ec8fe3c0a8ea8e3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 905903
Reviewed-on: https://chromium-review.googlesource.com/c/1411337
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#622794}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: ab41c2866ed57abc1f778496440e84a7023a787c
1 file changed