Removes usage of aura::Window from Node

mojo/services/view_manager/default_access_policy.cc

Index: mojo/services/view_manager/default_access_policy.cc
diff --git a/mojo/services/view_manager/default_access_policy.cc b/mojo/services/view_manager/default_access_policy.cc
index 7f87051f0b6e115ffea0b95ae75596cdabfbb3eb..39b0062ee4ebe59f0180e89e3e684bb256a4566b 100644
--- a/mojo/services/view_manager/default_access_policy.cc
+++ b/mojo/services/view_manager/default_access_policy.cc
@@ -23,8 +23,8 @@ bool DefaultAccessPolicy::CanRemoveNodeFromParent(const Node* node) const {
   if (!WasCreatedByThisConnection(node))
     return false;  // Can only unparent nodes we created.
 
-  const Node* parent = node->GetParent();
-  return IsNodeInRoots(parent) || WasCreatedByThisConnection(parent);
+  return IsNodeInRoots(node->parent()) ||
+      WasCreatedByThisConnection(node->parent());
 }
 
 bool DefaultAccessPolicy::CanAddNode(const Node* parent,