Files.app: Explicitly add o+r permission to mounted zip archives under Downloads.

Files.app: Explicitly add o+r permission to mounted zip archives under Downloads.

After the change r274593, downloaded files started to have permission 0640
rather than 0644. This CL explicitly adds read-permission before mounting,
provided the archive file is located under the local Downloads folder.

The modification is not applied to zip files on external storage because (1) the
silent change of permission may not be what the user want, (2) it should be rare
that download destination is set to removable devices, and (3) according to UMA
stat 99% of mounted filesystems are those we mount ignoring permissions anyhow
(FAT, NTFS, ISO9660, ...).

BUG=381144
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=275777

[hashimoto, 2014-06-09 04:44:14]

lgtm

[kinaba, 2014-06-09 05:25:58]

The CQ bit was checked by kinaba@chromium.org

[commit-bot: I haz the power, 2014-06-09 05:26:11]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/kinaba@chromium.org/323783002/1

[commit-bot: I haz the power, 2014-06-09 06:51:20]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  ios_rel_device_ninja on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_rel_device_ninja/...)

[commit-bot: I haz the power, 2014-06-09 06:59:21]

Change committed as 275777