Convert //ash from scoped_ptr to std::unique_ptr

ash/shell/window_watcher.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 "ash/shell/window_watcher.h"
 
 #include <utility>
 
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/shelf/shelf.h"
@@ skipping 100 matching lines @@
                         image_count == 0 ? 255 : 0,
                         image_count == 1 ? 255 : 0,
                         image_count == 2 ? 255 : 0);
   image_count = (image_count + 1) % 3;
   item.image = gfx::ImageSkia(gfx::ImageSkiaRep(icon_bitmap, 1.0f));
 
   model->Add(item);
 
   ShelfItemDelegateManager* manager =
       Shell::GetInstance()->shelf_item_delegate_manager();
-  scoped_ptr<ShelfItemDelegate> delegate(
+  std::unique_ptr<ShelfItemDelegate> delegate(
       new WindowWatcherShelfItemDelegate(id, this));
   manager->SetShelfItemDelegate(id, std::move(delegate));
   SetShelfIDForWindow(id, new_window);
 }
 
 void WindowWatcher::OnWillRemoveWindow(aura::Window* window) {
   for (IDToWindow::iterator i = id_to_window_.begin();
        i != id_to_window_.end(); ++i) {
     if (i->second == window) {
       ShelfModel* model = Shell::GetInstance()->shelf_model();
@@ skipping 16 matching lines @@
 void WindowWatcher::OnDisplayRemoved(const gfx::Display& old_display) {
   // All windows in the display has already been removed, so no need to
   // remove observers.
 }
 
 void WindowWatcher::OnDisplayMetricsChanged(const gfx::Display&, uint32_t) {
 }
 
 }  // namespace shell
 }  // namespace ash