Extend StrikeDatabase histograms by a year

These metrics are useful and help expose gaps in other metrics. We
intend to continue using them, so I'm extending them for another year.

Bug: 933189
Change-Id: I990454275de3aa9d3dc1d50064c5317babbaf9bc
Reviewed-on: https://chromium-review.googlesource.com/c/1478303
Commit-Queue: Jared Saul <jsaul@google.com>
Commit-Queue: Ilya Sherman <isherman@chromium.org>
Auto-Submit: Jared Saul <jsaul@google.com>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#633557}
1 file changed