Update window_parenting_utils to use aura::window

ash/common/wm/dock/docked_window_resizer.cc

Index: ash/common/wm/dock/docked_window_resizer.cc
diff --git a/ash/common/wm/dock/docked_window_resizer.cc b/ash/common/wm/dock/docked_window_resizer.cc
index f2ea238d33dc9ccd9be4789d6c6a8374a2bab216..e50ecd03be72a07a4af2ce0fd043e8bd7f7a2bf2 100644
--- a/ash/common/wm/dock/docked_window_resizer.cc
+++ b/ash/common/wm/dock/docked_window_resizer.cc
@@ -188,8 +188,9 @@ void DockedWindowResizer::StartedDragging(
     WmWindow* docked_container =
         GetTarget()->GetRootWindow()->GetChildByShellWindowId(
             kShellWindowId_DockedContainer);
-    wm::ReparentChildWithTransientChildren(
-        GetTarget(), GetTarget()->GetParent(), docked_container);
+    wm::ReparentChildWithTransientChildren(GetTarget()->aura_window(),
+                                           GetTarget()->aura_window()->parent(),
+                                           docked_container->aura_window());
     if (!resizer)
       return;
   }
@@ -266,8 +267,9 @@ DockedAction DockedWindowResizer::MaybeReparentWindowOnDragCompletion(
   if ((is_resized || !is_attached_panel) &&
       is_docked_ != (window->GetParent() == dock_container)) {
     if (is_docked_) {
-      wm::ReparentChildWithTransientChildren(window, window->GetParent(),
-                                             dock_container);
+      wm::ReparentChildWithTransientChildren(window->aura_window(),
+                                             window->aura_window()->parent(),
+                                             dock_container->aura_window());
       action = DOCKED_ACTION_DOCK;
     } else if (window->GetParent()->GetShellWindowId() ==
                kShellWindowId_DockedContainer) {
@@ -279,11 +281,12 @@ DockedAction DockedWindowResizer::MaybeReparentWindowOnDragCompletion(
       // mouse is).
       gfx::Rect near_last_location(last_location_, gfx::Size());
       // Reparenting will cause Relayout and possible dock shrinking.
-      WmWindow* previous_parent = window->GetParent();
+      aura::Window* previous_parent = window->aura_window()->parent();
       window->SetParentUsingContext(window, near_last_location);
-      if (window->GetParent() != previous_parent) {
-        wm::ReparentTransientChildrenOfChild(window, previous_parent,
-                                             window->GetParent());
+      if (window->aura_window()->parent() != previous_parent) {
+        wm::ReparentTransientChildrenOfChild(window->aura_window(),
+                                             previous_parent,
+                                             window->aura_window()->parent());
       }
       action = was_docked_ ? DOCKED_ACTION_UNDOCK : DOCKED_ACTION_NONE;
     }