Convert //ash from scoped_ptr to std::unique_ptr

ash/wm/overview/window_grid.h

 // 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.
 
 #ifndef ASH_WM_OVERVIEW_WINDOW_GRID_H_
 #define ASH_WM_OVERVIEW_WINDOW_GRID_H_
 
 #include <stddef.h>
 
+#include <memory>
 #include <set>
 #include <vector>
 
 #include "ash/wm/overview/window_selector.h"
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 #include "ui/aura/window_observer.h"
 
 namespace aura {
 class Window;
 }
 
 namespace views {
 class Widget;
 }
 
@@ skipping 100 matching lines @@
   // Pointer to the window selector that spawned this grid.
   WindowSelector* window_selector_;
 
   // Vector containing all the windows in this grid.
   ScopedVector<WindowSelectorItem> window_list_;
 
   // Vector containing the observed windows.
   std::set<aura::Window*> observed_windows_;
 
   // Widget that indicates to the user which is the selected window.
-  scoped_ptr<views::Widget> selection_widget_;
+  std::unique_ptr<views::Widget> selection_widget_;
 
   // Current selected window position.
   size_t selected_index_;
 
   // Number of columns in the grid.
   size_t num_columns_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowGrid);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_OVERVIEW_WINDOW_GRID_H_