Fix a threading issue and modernize the use of scoped_refptr in the on-demand update checker.

Fix a threading issue and modernize the use of scoped_refptr in the on-demand update checker.

The vector of delegates_ was previously being walked on the FILE
thread. This could lead to a crash if a new delegate were to be added on
the UI thread. Now, the driver bounces back to the UI thread to send
progress updates to the delegates.

Also changes the use of scoped_refptr to be up-to-date with current
style.

BUG=none
R=pmonette@chromium.org

Committed: https://crrev.com/4fe383ad8010911173d08a19baa3805d9d6f9269
Cr-Commit-Position: refs/heads/master@{#407726}

[grt (UTC plus 2), 2016-07-25 08:34:39]

The CQ bit was checked by grt@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-25 08:34:51]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[grt (UTC plus 2), 2016-07-25 08:35:05]

PTAL

[commit-bot: I haz the power, 2016-07-25 09:14:50]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-25 09:14:50]

Dry run: This issue passed the CQ dry run.

[Patrick Monette, 2016-07-25 17:23:55]

The CQ bit was checked by pmonette@chromium.org

[Patrick Monette, 2016-07-25 17:23:56]

lgtm

[Patrick Monette, 2016-07-25 17:24:24]

The CQ bit was unchecked by pmonette@chromium.org

[grt (UTC plus 2), 2016-07-25 17:28:05]

grt@chromium.org changed reviewers:
+ pkasting@chromium.org

[grt (UTC plus 2), 2016-07-25 17:28:05]

+PK for OWNERS review. Please feel at liberty to check the CQ box if it looks
good to you, thanks.

[Peter Kasting, 2016-07-25 19:02:47]

LGTM

[grt (UTC plus 2), 2016-07-26 06:55:12]

The CQ bit was checked by grt@chromium.org

[commit-bot: I haz the power, 2016-07-26 06:55:32]

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, 2016-07-26 06:59:07]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-26 07:00:34]

Description was changed from

==========
Fix a threading issue and modernize the use of scoped_refptr in the on-demand
update checker.

The vector of delegates_ was previously being walked on the FILE
thread. This could lead to a crash if a new delegate were to be added on
the UI thread. Now, the driver bounces back to the UI thread to send
progress updates to the delegates.

Also changes the use of scoped_refptr to be up-to-date with current
style.

BUG=none
R=pmonette@chromium.org
==========

to

==========
Fix a threading issue and modernize the use of scoped_refptr in the on-demand
update checker.

The vector of delegates_ was previously being walked on the FILE
thread. This could lead to a crash if a new delegate were to be added on
the UI thread. Now, the driver bounces back to the UI thread to send
progress updates to the delegates.

Also changes the use of scoped_refptr to be up-to-date with current
style.

BUG=none
R=pmonette@chromium.org

Committed: https://crrev.com/4fe383ad8010911173d08a19baa3805d9d6f9269
Cr-Commit-Position: refs/heads/master@{#407726}
==========

[commit-bot: I haz the power, 2016-07-26 07:00:35]

Patchset 1 (id:??) landed as
https://crrev.com/4fe383ad8010911173d08a19baa3805d9d6f9269
Cr-Commit-Position: refs/heads/master@{#407726}