Ash window cycle ui: don't create mirrored layers for previews until

ash/aura/wm_window_aura.cc

 // 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/aura/wm_window_aura.h"
 
 #include "ash/aura/aura_layout_manager_adapter.h"
 #include "ash/aura/wm_root_window_controller_aura.h"
 #include "ash/aura/wm_shell_aura.h"
 #include "ash/common/ash_constants.h"
@@ skipping 672 matching lines @@
       mouse_extend.Scale(kResizeOutsideBoundsScaleForTouch);
   window_->SetEventTargeter(base::WrapUnique(
       new ::wm::EasyResizeWindowTargeter(window_, mouse_extend, touch_extend)));
 }
 
 void WmWindowAura::SetDescendantsStayInSameRootWindow(bool value) {
   window_->SetProperty(kStayInSameRootWindowKey, true);
 }
 
 std::unique_ptr<views::View> WmWindowAura::CreateViewWithRecreatedLayers() {
-  std::unique_ptr<wm::WindowMirrorView> view(new wm::WindowMirrorView(this));
-  view->Init();
-  return std::move(view);
+  return base::WrapUnique(new wm::WindowMirrorView(this));
 }
 
 void WmWindowAura::AddObserver(WmWindowObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void WmWindowAura::RemoveObserver(WmWindowObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
@@ skipping 118 matching lines @@
                     OnTransientChildAdded(this, Get(transient)));
 }
 
 void WmWindowAura::OnTransientChildRemoved(aura::Window* window,
                                            aura::Window* transient) {
   FOR_EACH_OBSERVER(WmTransientWindowObserver, transient_observers_,
                     OnTransientChildRemoved(this, Get(transient)));
 }
 
 }  // namespace ash