arc: Cleanup legacy Play Store app id.

We switched to new unified (Android Play Store and ARC++ OptIn UI) Play
Store id year ago. Now it is time to clean up conversion code.

Test: Manually, no problem observed. Positions are preserved.
Bug: 722675
Change-Id: Ief70ea26b6ec1b446c72fed63ffec8edf56bb956
Reviewed-on: https://chromium-review.googlesource.com/1062218
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Yury Khmel <khmel@google.com>
Cr-Commit-Position: refs/heads/master@{#559232}
5 files changed