Removes aura::Window::set_user_data()

ui/aura/window.cc

 // Copyright (c) 2012 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 "ui/aura/window.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <utility>
@@ skipping 41 matching lines @@
     : port_owner_(std::move(port)),
       port_(port_owner_.get()),
       host_(nullptr),
       type_(ui::wm::WINDOW_TYPE_UNKNOWN),
       owned_by_parent_(true),
       delegate_(delegate),
       parent_(nullptr),
       visible_(false),
       id_(kInitialId),
       transparent_(false),
-      user_data_(nullptr),
       ignore_events_(false),
       // Don't notify newly added observers during notification. This causes
       // problems for code that adds an observer as part of an observer
       // notification (such as the workspace code).
       observers_(base::ObserverList<WindowObserver>::NOTIFY_EXISTING_ONLY) {
   SetTargetHandler(delegate_);
 }
 
 Window::~Window() {
   // See comment in header as to why this is done.
@@ skipping 1043 matching lines @@
     layer_name = "Unnamed Window";
 
   if (id_ != -1)
     layer_name += " " + base::IntToString(id_);
 
   layer()->set_name(layer_name);
 #endif
 }
 
 }  // namespace aura