GitLab

Clipboard history will now show the actual file names of files copied
from the File Manager.

This CL pulls logic out into ash::clipboard::helper to facilitate easier
testing.

Bug: 1108901
Change-Id: I3b66bb11b7bd0f0682e9870625ab724c643d37a4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2324557
Commit-Queue: David Black <dmblack@google.com>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#793377}