GitLab

This CL utilizes the mapping between account ids and history clipboard
data to handle the multi-user environment.

A browser test is created to protect this feature.

Bug: 1106857
Change-Id: I76d4d7ee2dc5b9525e4173586df168266a7fbb59
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2310848
Commit-Queue: Andrew Xu <andrewxu@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791366}