Update minimum space for migration to 50MB

Update minimum space for migration to 50MB

Users with large numbers of directories may require more space overhead
as any given directory tree may be duplicated on both source and
destination.  Increase the minimum migration storage space to account
for this.

BUG=737343
TEST=Fill disk and attempt to migrate

Review-Url: https://codereview.chromium.org/2968643002
Cr-Commit-Position: refs/heads/master@{#483940}
Committed: https://chromium.googlesource.com/chromium/src/+/55067bd6ae2557dd1ca2ef1dcf796fe7d2175456

[dspaid, 2017-06-30 07:06:23]

dspaid@chromium.org changed reviewers:
+ fukino@chromium.org

[dspaid, 2017-06-30 07:06:24]

PTAL
I verified that we do insert this constant into the UI strings in
encryption_migration_screen_handler.cc:475

[fukino, 2017-06-30 07:17:18]

lgtm. Thanks!

[dspaid, 2017-07-03 00:37:19]

dspaid@chromium.org changed reviewers:
+ hidehiko@chromium.org

[dspaid, 2017-07-03 00:37:19]

+hidehiko@ for OWNERS

[hidehiko, 2017-07-03 02:32:35]

lgtm

[dspaid, 2017-07-03 04:04:18]

The CQ bit was checked by dspaid@chromium.org

[commit-bot: I haz the power, 2017-07-03 04:04:31]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-07-03 04:33:57]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1499054658679690,
"parent_rev": "926329391ace2c7470f55b275988a09f4f1fd06b", "commit_rev":
"55067bd6ae2557dd1ca2ef1dcf796fe7d2175456"}

[commit-bot: I haz the power, 2017-07-03 04:34:10]

Description was changed from

==========
Update minimum space for migration to 50MB

Users with large numbers of directories may require more space overhead
as any given directory tree may be duplicated on both source and
destination.  Increase the minimum migration storage space to account
for this.

BUG=737343
TEST=Fill disk and attempt to migrate
==========

to

==========
Update minimum space for migration to 50MB

Users with large numbers of directories may require more space overhead
as any given directory tree may be duplicated on both source and
destination.  Increase the minimum migration storage space to account
for this.

BUG=737343
TEST=Fill disk and attempt to migrate

Review-Url: https://codereview.chromium.org/2968643002
Cr-Commit-Position: refs/heads/master@{#483940}
Committed:
https://chromium.googlesource.com/chromium/src/+/55067bd6ae2557dd1ca2ef1dcf79...
==========

[commit-bot: I haz the power, 2017-07-03 04:34:12]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/55067bd6ae2557dd1ca2ef1dcf79...