Removes aura dependencies from WindowPositioner

ash/shell/toplevel_window.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/toplevel_window.h"
 
 #include "ash/shell.h"
 #include "ash/wm/window_positioner.h"
 #include "ash/wm/window_state.h"
 #include "ash/wm/window_state_aura.h"
@@ skipping 66 matching lines @@
     gfx::Rect* bounds,
     ui::WindowShowState* show_state) const {
   bool is_saved_bounds = !!saved_state;
   if (saved_state && params_.use_saved_placement) {
     *bounds = saved_state->bounds;
     *show_state = saved_state->show_state;
   } else {
     // Initial default bounds.
     bounds->SetRect(10, 150, 300, 300);
   }
-  ash::WindowPositioner::GetBoundsAndShowStateForNewWindow(
-      gfx::Screen::GetScreen(), NULL, is_saved_bounds, *show_state, bounds,
-      show_state);
+  WindowPositioner::GetBoundsAndShowStateForNewWindow(
+      nullptr, is_saved_bounds, *show_state, bounds, show_state);
   return true;
 }
 
 views::View* ToplevelWindow::GetContentsView() {
   return this;
 }
 
 bool ToplevelWindow::CanResize() const {
   return params_.can_resize;
 }
 
 bool ToplevelWindow::CanMaximize() const {
   return params_.can_maximize;
 }
 
 bool ToplevelWindow::CanMinimize() const {
   return params_.can_maximize;
 }
 
 }  // namespace shell
 }  // namespace ash