Fixes _NET_ACTIVE_WINDOW support check in order to not always return no.

Fixes _NET_ACTIVE_WINDOW support check in order to not always return no.

The check is currently not working on Unity because it expects an array
of atoms instead of one XID. With this patch, Unity is correctly seen
as supporting the feature.

BUG=None

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=246270

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=246520

[mlamouri (slow - plz ping), 2014-01-21 06:46:42]

Oups, I was a bit too fast to send that, I removed important bits in my rebase.
PTAL.

[Elliot Glaysher, 2014-01-21 19:02:57]

lgtm

[commit-bot: I haz the power, 2014-01-21 22:55:19]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mlamouri@chromium.org/138903007/40001

[commit-bot: I haz the power, 2014-01-22 01:03:04]

Retried try job too often on linux_chromeos for step(s) interactive_ui_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_chro...

[commit-bot: I haz the power, 2014-01-22 04:06:42]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mlamouri@chromium.org/138903007/40001

[commit-bot: I haz the power, 2014-01-22 10:23:41]

Change committed as 246270

[Mattias Nissler (ping if slow), 2014-01-22 13:12:22]

A revert of this CL has been created in
https://codereview.chromium.org/144003015/ by mnissler@chromium.org.

The reason for reverting is: Speculative revert for
DesktopScreenX11Test.GetWindowAtScreenPoint test failure on Linux Aura Tests
bot:

http://build.chromium.org/p/chromium.linux/builders/Linux%20Aura%20Tests/buil...

[ RUN      ] DesktopScreenX11Test.GetWindowAtScreenPoint
Xlib:  extension "RANDR" missing on display ":9".
../../ui/views/widget/desktop_aura/desktop_screen_x11_unittest.cc:227: Failure
Value of: screen()->GetWindowAtScreenPoint(gfx::Point(115, 115))
  Actual: 0x7f84f619fc00
Expected: window_three->GetNativeWindow()
Which is: 0x1fbfcfb82200
[  FAILED  ] DesktopScreenX11Test.GetWindowAtScreenPoint (82 ms).

[mlamouri (slow - plz ping), 2014-01-22 23:53:42]

sadrul@, could you have a look at the change that I made in order to make the
test pass?

[sadrul, 2014-01-23 00:04:44]

LGTM

It might be useful to have a WaitUntilActive(Window) function that spins up a
nested message-loop and blocks until Window is active (and other such methods
for the desired Window state), so that we can use that in tests in other places.
This is probably not necessary yet, but it may come in handy as we add more
tests.

[commit-bot: I haz the power, 2014-01-23 00:07:43]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mlamouri@chromium.org/138903007/350001

[commit-bot: I haz the power, 2014-01-23 04:13:55]

Change committed as 246520