Fix the size of the tabs when exiting immersive fullscreen with the tab indicators hidden

Fix the size of the tabs when exiting immersive fullscreen with the tab indicators hidden.

The following occurs when exiting immersive fullscreen, in order:
1) The aura::Window's kShowStateKey is updated. This causes a layout of the BrowserView's non client view. (Note that BrowserView::ProcessFullscreen() does not disable laying out the non client view.)
2) Immersive fullscreen is disabled
3) BrowserView::Layout()

This CL fixes a bug where the y position of the browser view in its parent is incorrect due to BrowserView::IsFullscreen() returning false and ImmersiveModeController::IsEnabled() returning true during step 1.

BUG=233271
Test=Manual, see repro steps below
1) Run chrome with --ash-immersive-hide-tab-indicators --ash-enable-immersive-fullscreen
2) Use F4 to enter immersive fullscreen
3) With the top-of-window views hidden, hit F4 to exit immersive fullscreen
4) The tab strip should be properly visible

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=198558

[pkotwicz, 2013-05-04 00:30:02]

James PTAL.
This fixes a regression because of
https://chromiumcodereview.appspot.com/14340007

[James Cook, 2013-05-05 22:04:31]

LGTM

[commit-bot: I haz the power, 2013-05-06 16:01:58]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pkotwicz@chromium.org/14634003/4001

[commit-bot: I haz the power, 2013-05-06 22:54:13]

Change committed as 198558