Ignore fullscreen windows which are behind other windows for fullscreen mode.

ash/system/web_notification/web_notification_tray_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/system/web_notification/web_notification_tray.h"
 
 #include <vector>
 
 #include "ash/display/display_manager.h"
 #include "ash/root_window_controller.h"
@@ skipping 416 matching lines @@
   shelf->SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS);
   EXPECT_EQ(SHELF_AUTO_HIDE_HIDDEN, shelf->auto_hide_state());
   gfx::Rect work_area_auto_hidden = GetPopupWorkArea();
   shelf->SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_NEVER);
 
   // Put |window| into fullscreen without forcing the shelf to hide. Currently,
   // this is used by immersive fullscreen and forces the shelf to be auto
   // hidden.
   wm::GetWindowState(window.get())->set_hide_shelf_when_fullscreen(false);
   window->SetProperty(aura::client::kShowStateKey, ui::SHOW_STATE_FULLSCREEN);
+  wm::GetWindowState(window.get())->Activate();
   RunAllPendingInMessageLoop();
 
   // The work area for auto-hidden status of fullscreen is a bit larger
   // since it doesn't even have the 3-pixel width.
   EXPECT_EQ(SHELF_AUTO_HIDE_HIDDEN, shelf->auto_hide_state());
   gfx::Rect work_area_fullscreen_hidden = GetPopupWorkArea();
   EXPECT_EQ(work_area_auto_hidden.ToString(),
             work_area_fullscreen_hidden.ToString());
 
   // Move the mouse cursor at the bottom, which shows the shelf.
@@ skipping 21 matching lines @@
 
   // System tray is created on the primary display. The popups in the secondary
   // tray aren't affected.
   GetSystemTray()->ShowDefaultView(BUBBLE_CREATE_NEW);
   EXPECT_GT(work_area.size().GetArea(), GetPopupWorkArea().size().GetArea());
   EXPECT_EQ(work_area_second.ToString(),
             GetPopupWorkAreaForTray(GetSecondaryTray()).ToString());
 }
 
 }  // namespace ash