Add the flag to enable/disable the recent fixes to Language Settings.

We have been working on fixing the main bugs with Language Settings
for a while and we are ready to do the final manual testing and launch.

Bug: 640763
Change-Id: I9dba8e4087267f094b98d0029696bb09f196c86b
Reviewed-on: https://chromium-review.googlesource.com/845241
Reviewed-by: Renjie Liu <[email protected]>
Commit-Queue: Claudio M <[email protected]>
Cr-Commit-Position: refs/heads/master@{#526268}
3 files changed