mash: remove more shell/shelf WmWindow usage.

ash/wm/drag_window_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/drag_window_controller.h"
 
 #include <algorithm>
 
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/shell.h"
@@ skipping 19 matching lines @@
 #include "ui/wm/core/window_util.h"
 
 namespace ash {
 
 // This keeps track of the drag window's state. It creates/destroys/updates
 // bounds and opacity based on the current bounds.
 class DragWindowController::DragWindowDetails : public aura::WindowDelegate {
  public:
   DragWindowDetails(const display::Display& display,
                     aura::Window* original_window)
-      : root_window_(ShellPort::Get()
-                         ->GetRootWindowForDisplayId(display.id())
-                         ->aura_window()) {}
+      : root_window_(
+            ShellPort::Get()->GetRootWindowForDisplayId(display.id())) {}
 
   ~DragWindowDetails() override {
     delete drag_window_;
     DCHECK(!drag_window_);
   }
 
   void Update(aura::Window* original_window,
               const gfx::Rect& bounds_in_screen,
               const gfx::Point& drag_location_in_screen) {
     gfx::Rect root_bounds_in_screen = root_window_->GetBoundsInScreen();
@@ skipping 192 matching lines @@
       layers.pop_back();
       if (layer->delegate())
         layer->delegate()->OnPaintLayer(context);
       for (auto* child : layer->children())
         layers.push_back(child);
     }
   }
 }
 
 }  // namespace ash