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

ash/wm/overview/window_selector_unittest.cc

 // Copyright 2013 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/launcher/launcher.h"
 #include "ash/root_window_controller.h"
 #include "ash/screen_ash.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
@@ skipping 266 matching lines @@
 
   // The panel becomes temporarily visible for the overview.
   EXPECT_TRUE(panel1->IsVisible());
   ClickWindow(window1.get());
 
   // The window is still fullscreen as it was selected. The panel should again
   // be hidden.
   EXPECT_TRUE(wm::GetWindowState(window1.get())->IsFullscreen());
   EXPECT_FALSE(panel1->IsVisible());
 
-  // Entering overview and selecting another window should exit fullscreen.
+  // Entering overview and selecting another window, the previous window remains
+  // fullscreen.
   // TODO(flackr): Currently the panel remains hidden, but should become visible
   // again.
   ToggleOverview();
   ClickWindow(window2.get());
-  EXPECT_FALSE(wm::GetWindowState(window1.get())->IsFullscreen());
+  EXPECT_TRUE(wm::GetWindowState(window1.get())->IsFullscreen());
 }
 
 // Tests that the shelf dimming state is removed while in overview and restored
 // on exiting overview.
 TEST_F(WindowSelectorTest, OverviewUndimsShelf) {
   gfx::Rect bounds(0, 0, 400, 400);
   scoped_ptr<aura::Window> window1(CreateWindow(bounds));
   wm::WindowState* window_state = wm::GetWindowState(window1.get());
   window_state->Maximize();
   ash::ShelfWidget* shelf = Shell::GetPrimaryRootWindowController()->shelf();
@@ skipping 637 matching lines @@
       ToEnclosingRect(GetTransformedTargetBounds(window1.get()));
   EXPECT_EQ(overview_bounds.x(), new_overview_bounds.x());
   EXPECT_EQ(overview_bounds.y(), new_overview_bounds.y());
   EXPECT_EQ(overview_bounds.width(), new_overview_bounds.width());
   EXPECT_EQ(overview_bounds.height(), new_overview_bounds.height());
   StopCycling();
 }
 
 }  // namespace internal
 }  // namespace ash