[M55] Generalize layer mirroring for phantom windows

ash/utility/screenshot_controller.cc

 // Copyright 2014 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/utility/screenshot_controller.h"
 
 #include <cmath>
 
 #include "ash/common/shell_window_ids.h"
 #include "ash/display/mouse_cursor_event_filter.h"
@@ skipping 70 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(ScreenshotWindowTargeter);
 };
 
 }  // namespace
 
 class ScreenshotController::ScreenshotLayer : public ui::LayerOwner,
                                               public ui::LayerDelegate {
  public:
   ScreenshotLayer(ui::Layer* parent, bool immediate_overlay)
       : draw_inactive_overlay_(immediate_overlay) {
-    SetLayer(new ui::Layer(ui::LAYER_TEXTURED));
+    SetLayer(base::MakeUnique<ui::Layer>(ui::LAYER_TEXTURED));
     layer()->SetFillsBoundsOpaquely(false);
     layer()->SetBounds(parent->bounds());
     parent->Add(layer());
     parent->StackAtTop(layer());
     layer()->SetVisible(true);
     layer()->set_delegate(this);
   }
   ~ScreenshotLayer() override {}
 
   const gfx::Rect& region() const { return region_; }
@@ skipping 440 matching lines @@
 
 void ScreenshotController::OnDisplayMetricsChanged(
     const display::Display& display,
     uint32_t changed_metrics) {}
 
 void ScreenshotController::OnWindowDestroying(aura::Window* window) {
   SetSelectedWindow(nullptr);
 }
 
 }  // namespace ash