Makes Panel related classes use ash/wm/common types

ash/wm/dock/docked_window_resizer_unittest.cc

 // Copyright (c) 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/wm/dock/docked_window_resizer.h"
 
 #include "ash/ash_switches.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/root_window_controller.h"
 #include "ash/screen_util.h"
@@ skipping 65 matching lines @@
   aura::Window* CreateTestWindow(const gfx::Rect& bounds) {
     aura::Window* window = CreateTestWindowInShellWithDelegateAndType(
         &delegate_,
         window_type_,
         0,
         bounds);
     if (window_type_ == ui::wm::WINDOW_TYPE_PANEL) {
       test::TestShelfDelegate* shelf_delegate =
           test::TestShelfDelegate::instance();
       shelf_delegate->AddShelfItem(window);
-      PanelLayoutManager* manager = static_cast<PanelLayoutManager*>(
-          Shell::GetContainer(window->GetRootWindow(),
-                              kShellWindowId_PanelContainer)->layout_manager());
+      PanelLayoutManager* manager =
+          PanelLayoutManager::Get(wm::WmWindowAura::Get(window));
       manager->Relayout();
     }
     return window;
   }
 
   aura::Window* CreateModalWindow(const gfx::Rect& bounds) {
     aura::Window* window = new aura::Window(&delegate_);
     window->SetProperty(aura::client::kModalKey, ui::MODAL_TYPE_SYSTEM);
     window->SetType(ui::wm::WINDOW_TYPE_NORMAL);
     window->Init(ui::LAYER_TEXTURED);
@@ skipping 1517 matching lines @@
   EXPECT_TRUE(window_state->IsMaximized());
 }
 
 // Tests run twice - on both panels and normal windows
 INSTANTIATE_TEST_CASE_P(NormalOrPanel,
                         DockedWindowResizerTest,
                         testing::Values(ui::wm::WINDOW_TYPE_NORMAL,
                                         ui::wm::WINDOW_TYPE_PANEL));
 
 }  // namespace ash