Convert //ash from scoped_ptr to std::unique_ptr

ash/wm/workspace_controller.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/wm/workspace_controller.h"
 
 #include <utility>
 
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_layout_manager.h"
@@ skipping 116 matching lines @@
             ui::LayerAnimationElement::VISIBILITY);
     settings.SetTweenType(gfx::Tween::EASE_OUT);
     settings.SetTransitionDuration(
         base::TimeDelta::FromMilliseconds(kCrossFadeDurationMS));
     viewport_->layer()->SetTransform(gfx::Transform());
     viewport_->layer()->SetOpacity(1.0f);
   }
 }
 
 void WorkspaceController::SetMaximizeBackdropDelegate(
-    scoped_ptr<WorkspaceLayoutManagerDelegate> delegate) {
+    std::unique_ptr<WorkspaceLayoutManagerDelegate> delegate) {
   layout_manager_->SetMaximizeBackdropDelegate(std::move(delegate));
 }
 
 }  // namespace ash