Revert "Enable file upload by default."

This reverts commit 507521d5cc46ffd8e02ba54133fc9c57db8070d1.

Reason for revert: We wanted this for testing prior to release, but we don't want it in the release branch until we've gone through security review.

Original change's description:
> Enable file upload by default.
> 
> Now that file upload has a cross-platform implementation, it should be
> safe to enable for testing and eventual rollout to the client. We
> decided we didn't need a Chrome policy for now, so enable
> unconditionally.
> 
> Bug: 679313
> Change-Id: I7abd23561d7c485191cfade854b0cfcc035e25be
> Reviewed-on: https://chromium-review.googlesource.com/c/1419097
> Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
> Reviewed-by: Joe Downing <joedow@chromium.org>
> Commit-Queue: Erik Jensen <rkjnsn@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#623947}

TBR=jamiewalch@chromium.org,joedow@chromium.org,rkjnsn@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 679313
Change-Id: I8479766fbdbfbca9a10c179c49cd745fe13904e2
Reviewed-on: https://chromium-review.googlesource.com/c/1434517
Reviewed-by: Joe Downing <joedow@chromium.org>
Commit-Queue: Erik Jensen <rkjnsn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625693}
1 file changed