[M55] Generalize layer mirroring for phantom windows

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 153 matching lines @@
   }
   prop_map_.clear();
 
   // The layer will either be destroyed by |layer_owner_|'s dtor, or by whoever
   // acquired it.
   layer()->set_delegate(NULL);
   DestroyLayer();
 }
 
 void Window::Init(ui::LayerType layer_type) {
-  SetLayer(new ui::Layer(layer_type));
+  SetLayer(base::MakeUnique<ui::Layer>(layer_type));
   layer()->SetVisible(false);
   layer()->set_delegate(this);
   UpdateLayerName();
   layer()->SetFillsBoundsOpaquely(!transparent_);
   Env::GetInstance()->NotifyWindowInitialized(this);
 }
 
 void Window::SetType(ui::wm::WindowType type) {
   // Cannot change type after the window is initialized.
   DCHECK(!layer());
@@ skipping 933 matching lines @@
     layer_name = "Unnamed Window";
 
   if (id_ != -1)
     layer_name += " " + base::IntToString(id_);
 
   layer()->set_name(layer_name);
 #endif
 }
 
 }  // namespace aura