Update window_parenting_utils to use aura::window

ash/common/wm/dock/docked_window_layout_manager.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/common/wm/dock/docked_window_layout_manager.h"
 
 #include "ash/animation/animation_change_type.h"
 #include "ash/common/shelf/shelf_background_animator.h"
 #include "ash/common/shelf/shelf_background_animator_observer.h"
 #include "ash/common/shelf/shelf_constants.h"
@@ skipping 166 matching lines @@
 bool IsWindowDocked(const WmWindow* window) {
   return (window->IsVisible() && !window->GetWindowState()->IsMinimized() &&
           !IsPopupOrTransient(window));
 }
 
 void UndockWindow(WmWindow* window) {
   gfx::Rect previous_bounds = window->GetBounds();
   WmWindow* old_parent = window->GetParent();
   window->SetParentUsingContext(window, gfx::Rect());
   if (window->GetParent() != old_parent) {
-    wm::ReparentTransientChildrenOfChild(window, old_parent,
-                                         window->GetParent());
+    wm::ReparentTransientChildrenOfChild(window->aura_window(),
+                                         old_parent->aura_window(),

[sky, 2017/03/09 20:57:45]

Similar comment about nullness for old_parent and GetParent().

[yiyix, 2017/03/09 22:00:15]

Done.

+                                         window->GetParent()->aura_window());
   }
   // Start maximize or fullscreen (affecting packaged apps) animation from
   // previous window bounds.
   window->GetLayer()->SetBounds(previous_bounds);
 }
 
 // Returns width that is as close as possible to |target_width| while being
 // consistent with docked min and max restrictions and respects the |window|'s
 // minimum and maximum size.
 int GetWindowWidthCloseTo(const WmWindow* window, int target_width) {
@@ skipping 1133 matching lines @@
     const gfx::Rect& keyboard_bounds) {
   // This bounds change will have caused a change to the Shelf which does not
   // propagate automatically to this class, so manually recalculate bounds.
   Relayout();
   UpdateDockBounds(DockedWindowLayoutManagerObserver::KEYBOARD_BOUNDS_CHANGING);
 }
 
 void DockedWindowLayoutManager::OnKeyboardClosed() {}
 
 }  // namespace ash