Make callers of FromUTC(Local)Exploded in base/ use new time API.

Use new time conversion API in accordance with
https://codereview.chromium.org/1988663002/

BUG=601900

Review-Url: https://codereview.chromium.org/2086393003
Cr-Commit-Position: refs/heads/master@{#402730}
4 files changed