Use WindowTracker when resizing root window as it may delete other window in unit tests.

ash/wm/panels/panel_layout_manager.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/wm/panels/panel_layout_manager.h"
 
 #include <algorithm>
 #include <map>
 
 #include "ash/screen_util.h"
@@ skipping 527 matching lines @@
 void PanelLayoutManager::WillChangeVisibilityState(
     ShelfVisibilityState new_state) {
   // On entering / leaving full screen mode the shelf visibility state is
   // changed to / from SHELF_HIDDEN. In this state, panel windows should hide
   // to allow the full-screen application to use the full screen.
   bool shelf_hidden = new_state == ash::SHELF_HIDDEN;
   if (!shelf_hidden) {
     if (restore_windows_on_shelf_visible_) {
       scoped_ptr<aura::WindowTracker> restore_windows(
           restore_windows_on_shelf_visible_.Pass());
-      for (aura::WindowTracker::Windows::const_iterator iter =
-           restore_windows->windows().begin(); iter !=
-           restore_windows->windows().end(); ++iter) {
+      for (aura::Window::Windows::const_iterator iter =
+               restore_windows->windows().begin();
+           iter != restore_windows->windows().end(); ++iter) {
         RestorePanel(*iter);
       }
     }
     return;
   }
 
   if (restore_windows_on_shelf_visible_)
     return;
   scoped_ptr<aura::WindowTracker> minimized_windows(new aura::WindowTracker);
   for (PanelList::iterator iter = panel_windows_.begin();
@@ skipping 390 matching lines @@
       // Keyboard hidden, restore original bounds if they exist.
       SetChildBounds(panel, panel_state->GetRestoreBoundsInScreen());
     }
   }
   // This bounds change will have caused a change to the Shelf which does not
   // propogate automatically to this class, so manually recalculate bounds.
   OnWindowResized();
 }
 
 }  // namespace ash