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- This CL creates utils for update notification service.
- Implemented and tested CalculateDeliverTime, which will
be used in building notification params.

Bug: 1013685
Change-Id: Ibdf465e9b1d0285c02bac8bca5ac602e2b048e01
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1947923Reviewed-by: Xing Liu <xingliu@chromium.org>
Commit-Queue: Hesen Zhang <hesen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721815}