[jumbo] Deduplicate a time constant in autofill code

Two different bubbles needed the same time constant and when
they got copies of the constant that broke certain jumbo
builds. This merges the constants to a single constant.

It also changes type to base::TimeDelta which is the actual
type needed and since the addition of constexpr can be used
in global constants.

Bug: 852904,862397
Change-Id: I52a63d3301efb1c7aec55541c15427c5d96ba524
Reviewed-on: https://chromium-review.googlesource.com/1134998
Commit-Queue: Daniel Bratell <bratell@opera.com>
Commit-Queue: Mathieu Perreault <mathp@chromium.org>
Reviewed-by: Mathieu Perreault <mathp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574578}
4 files changed