GitLab

Add function computing the base::TimeDelta since the application
launch from kernel information about the process (based on the
implementation from google_toolbox_for_mac).

Bug: none
Change-Id: I5d70aa1f9bb76b1b22f8375c2e7e53319486e460
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1899994
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713431}