Add a Mac UMA for the filesystem where Chrome lives.

BUG=914393

Change-Id: Ia9813b162121de8c3763ccafc6525a628370f5ac
Reviewed-on: https://chromium-review.googlesource.com/c/1371936
Commit-Queue: Avi Drissman <avi@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#615934}(cherry picked from commit 753cb9dffd9887d9ce84ef3d3f546f10f91cf409)
Reviewed-on: https://chromium-review.googlesource.com/c/1388821
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/branch-heads/3626@{#504}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}
3 files changed