GitLab

1) Adds a UserAction for drag&drop so read access can be auto-granted
for directories when dropping. Without this websites would have to
explicitly request access after dropping a directory.

2) Adds a CanRequestReadPermission method that lets us block file
dialogs if read permission would be denied anyway. Currently read access
can't be denied yet, but enterprise policy might change that, so we
should at least deal with it properly.

Bug: 1053363, 1080811
Change-Id: I2a03c6d1c7d804de2eadc84a7aa13a0515d3d5df
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2353193Reviewed-by: Victor Costan <pwnall@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Auto-Submit: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797715}