Make WebContents get the correct screen coordinates when initially added.

Make WebContents get the correct screen coordinates when initially added.

This CL fixes an issue where combobox dropdowns would render in the wrong
place for tabs that were created in the background. This was happening
because the native view and clipping windows weren't being added in the
right order, causing the incorrect screen space coordinates to get
passed around.

BUG=394715
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284913

[sky, 2014-07-22 16:57:46]

LGTM
I don't think this effects estade's patch, but adding just in case.

[calamity, 2014-07-23 03:03:27]

The CQ bit was checked by calamity@chromium.org

[commit-bot: I haz the power, 2014-07-23 03:04:16]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/calamity@chromium.org/399343003/40001

[commit-bot: I haz the power, 2014-07-23 06:20:50]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)

[calamity, 2014-07-23 07:50:51]

The CQ bit was checked by calamity@chromium.org

[commit-bot: I haz the power, 2014-07-23 07:51:44]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/calamity@chromium.org/399343003/60001

[commit-bot: I haz the power, 2014-07-23 09:35:30]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  android_dbg_triggered_tests on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered...)

[commit-bot: I haz the power, 2014-07-23 14:09:50]

Change committed as 284913