Removes specifying transient at the aura level for top levels

Removes specifying transient at the aura level for top levels

This causes problems as it means the aura::Window may be deleted out
from under the DesktopNativeWidgetAura, which causes all sorts of woe.

This code is no longer needed since DesktopWindowTreeHostX11 now deals
with owned windows.

BUG=344265
TEST=none
R=erg@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=255377

[Elliot Glaysher, 2014-03-05 23:27:26]

lgtm

(Good luck!)

[sky, 2014-03-06 00:01:45]

The CQ bit was checked by sky@chromium.org

[commit-bot: I haz the power, 2014-03-06 00:26:28]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/sky@chromium.org/186483007/1

[commit-bot: I haz the power, 2014-03-06 02:27:14]

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

[commit-bot: I haz the power, 2014-03-06 02:27:14]

Retried try job too often on win_rel for step(s) ash_unittests,
telemetry_perf_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[sky, 2014-03-06 15:50:50]

The CQ bit was checked by sky@chromium.org

[commit-bot: I haz the power, 2014-03-06 15:50:57]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/sky@chromium.org/186483007/1

[commit-bot: I haz the power, 2014-03-06 17:08:02]

Change committed as 255377