mash: Don't crash when dragging a window to the side.

mash: Don't crash when dragging a window to the side.

WindowServer::GetTreeWithId can be null in the case of
|in_nonclient_area|. It looks like |tree| was used without check in
4d3588cbec.

BUG=630402
Committed: https://crrev.com/c0ddac38d03c1d91290494b5f6ee77347dba1505
Cr-Commit-Position: refs/heads/master@{#407181}

[Elliot Glaysher, 2016-07-21 21:09:17]

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

[commit-bot: I haz the power, 2016-07-21 21:09:42]

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

[Elliot Glaysher, 2016-07-21 21:22:09]

erg@chromium.org changed reviewers:
+ sadrul@chromium.org

[Elliot Glaysher, 2016-07-21 21:22:10]

I have low confidence in this fix, and it's more to sort of prod at this bug.
This does fix the crash though.

[commit-bot: I haz the power, 2016-07-21 22:03:16]

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

[commit-bot: I haz the power, 2016-07-21 22:03:17]

Dry run: This issue passed the CQ dry run.

[sadrul, 2016-07-22 03:29:49]

This looks like the right fix, actually (you will notice how we check for a
non-null tree in the while-loop right below the crashing code as well).

lgtm

[Elliot Glaysher, 2016-07-22 17:05:06]

The CQ bit was checked by erg@chromium.org

[commit-bot: I haz the power, 2016-07-22 17:05:40]

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, 2016-07-22 17:10:33]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-22 17:12:41]

Description was changed from

==========
mash: Don't crash when dragging a window to the side.

WindowServer::GetTreeWithId can be null in the case of
|in_nonclient_area|. It looks like |tree| was used without check in
4d3588cbec.

BUG=630402
==========

to

==========
mash: Don't crash when dragging a window to the side.

WindowServer::GetTreeWithId can be null in the case of
|in_nonclient_area|. It looks like |tree| was used without check in
4d3588cbec.

BUG=630402

Committed: https://crrev.com/c0ddac38d03c1d91290494b5f6ee77347dba1505
Cr-Commit-Position: refs/heads/master@{#407181}
==========

[commit-bot: I haz the power, 2016-07-22 17:12:42]

Patchset 1 (id:??) landed as
https://crrev.com/c0ddac38d03c1d91290494b5f6ee77347dba1505
Cr-Commit-Position: refs/heads/master@{#407181}