GitLab

This CL brings DateDividedAdapter to Chrome, and lets Download Manager
UI to utilize it. This adapter will take a list of timed items, groups
these items by date, and displays the groups in sections.

BUG=616324

Review-Url: https://codereview.chromium.org/2154063003
Cr-Commit-Position: refs/heads/master@{#406641}