Moves maintaining ShellObservers back to Shell

ash/wm/panels/attached_panel_window_targeter.cc

 // Copyright 2014 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/attached_panel_window_targeter.h"
 
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/wm/panels/panel_layout_manager.h"
-#include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
+#include "ash/shell.h"
 #include "ui/aura/window.h"
 
 namespace ash {
 
 AttachedPanelWindowTargeter::AttachedPanelWindowTargeter(
     aura::Window* container,
     const gfx::Insets& default_mouse_extend,
     const gfx::Insets& default_touch_extend,
     PanelLayoutManager* panel_layout_manager)
     : ::wm::EasyResizeWindowTargeter(container,
                                      default_mouse_extend,
                                      default_touch_extend),
       panel_container_(container),
       panel_layout_manager_(panel_layout_manager),
       default_touch_extend_(default_touch_extend) {
-  WmShell::Get()->AddShellObserver(this);
+  Shell::GetInstance()->AddShellObserver(this);
 }
 
 AttachedPanelWindowTargeter::~AttachedPanelWindowTargeter() {
-  WmShell::Get()->RemoveShellObserver(this);
+  Shell::GetInstance()->RemoveShellObserver(this);
 }
 
 void AttachedPanelWindowTargeter::OnShelfCreatedForRootWindow(
     WmWindow* root_window) {
   UpdateTouchExtend(WmWindow::GetAuraWindow(root_window));
 }
 
 void AttachedPanelWindowTargeter::OnShelfAlignmentChanged(
     WmWindow* root_window) {
   // Don't update the touch insets if the shelf has not yet been created.
@@ skipping 22 matching lines @@
           gfx::Insets(touch.top(), 0, touch.bottom(), touch.right()));
       break;
     case SHELF_ALIGNMENT_RIGHT:
       set_touch_extend(
           gfx::Insets(touch.top(), touch.left(), touch.bottom(), 0));
       break;
   }
 }
 
 }  // namespace ash