Revert "Android: Replace ConcurrentHashMap usage with Collections.synchronizedMap()"

This reverts commit b083d66bda71ca14e758550c9edb60ef236770b8.

Reason for revert: Realized forgot to synchronize iterators.

Original change's description:
> Android: Replace ConcurrentHashMap usage with Collections.synchronizedMap()
> ConcurrentHashMap has a bug on L.
> Also adds a checkstyle check to prevent future uses.
> Bug: 905903
> Change-Id: Ic6afed17b5d7d3c6a150935117fb33e0408955e4
> Reviewed-on:
> Reviewed-by: Tibor Goldschwendt <>
> Commit-Queue: agrieve <>
> Cr-Commit-Position: refs/heads/master@{#622143},

Change-Id: I64fa06d829df489fdf85249bc69331adc7df0031
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 905903
Reviewed-by: agrieve <>
Commit-Queue: agrieve <>
Cr-Original-Commit-Position: refs/heads/master@{#622284}
Cr-Mirrored-Commit: e0e82c93404791efbe187bfa1f9a8e72335dbd80
1 file changed