Removes most of aura dependencies from DefaultState

ash/wm/common/window_parenting_utils.cc

Index: ash/wm/common/window_parenting_utils.cc
diff --git a/ash/wm/common/window_parenting_utils.cc b/ash/wm/common/window_parenting_utils.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3df723a00fc669985114235b3a509cd0ae74ed41
--- /dev/null
+++ b/ash/wm/common/window_parenting_utils.cc
@@ -0,0 +1,29 @@
+// Copyright 2016 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/common/window_parenting_utils.h"
+
+#include "ash/wm/common/wm_window.h"
+
+namespace ash {
+namespace wm {
+
+void ReparentChildWithTransientChildren(WmWindow* child,
+                                        WmWindow* old_parent,
+                                        WmWindow* new_parent) {
+  if (child->GetParent() == old_parent)
+    new_parent->AddChild(child);
+  ReparentTransientChildrenOfChild(child, old_parent, new_parent);
+}
+
+void ReparentTransientChildrenOfChild(WmWindow* child,
+                                      WmWindow* old_parent,
+                                      WmWindow* new_parent) {
+  for (WmWindow* transient_child : child->GetTransientChildren()) {
+    ReparentChildWithTransientChildren(transient_child, old_parent, new_parent);
+  }

[oshima, 2016/04/18 22:15:52]

nit: nuke {}

[sky, 2016/04/20 00:08:49]

Done.

+}
+
+}  // namespace wm
+}  // namespace ash