Simplify calls for scale factor

ui/aura/window_tree_host_x11.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 "ui/aura/window_tree_host_x11.h"
 
 #include <strings.h>
 #include <X11/cursorfont.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/extensions/Xrandr.h>
@@ skipping 13 matching lines @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/sys_info.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/cursor/cursor.h"
+#include "ui/base/layout.h"
 #include "ui/base/platform_window_defaults.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/base/view_prop.h"
 #include "ui/base/x/x11_util.h"
 #include "ui/base/x/x11_window_event_manager.h"
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
 #include "ui/display/screen.h"
 #include "ui/events/devices/x11/device_data_manager_x11.h"
@@ skipping 352 matching lines @@
 }
 
 gfx::Rect WindowTreeHostX11::GetBoundsInPixels() const {
   return bounds_;
 }
 
 void WindowTreeHostX11::SetBoundsInPixels(const gfx::Rect& bounds) {
   // Even if the host window's size doesn't change, aura's root window
   // size, which is in DIP, changes when the scale changes.
   float current_scale = compositor()->device_scale_factor();
-  float new_scale = display::Screen::GetScreen()
-                        ->GetDisplayNearestWindow(window())
-                        .device_scale_factor();
+  float new_scale = ui::GetScaleFactorForNativeView(window());
   bool origin_changed = bounds_.origin() != bounds.origin();
   bool size_changed = bounds_.size() != bounds.size();
   XWindowChanges changes = {0};
   unsigned value_mask = 0;
 
   if (size_changed) {
     changes.width = bounds.width();
     changes.height = bounds.height();
     value_mask = CWHeight | CWWidth;
   }
@@ skipping 149 matching lines @@
     ui::LocatedEvent* event) {
   SendEventToProcessor(event);
 }
 
 // static
 WindowTreeHost* WindowTreeHost::Create(const gfx::Rect& bounds_in_pixels) {
   return new WindowTreeHostX11(bounds_in_pixels);
 }
 
 }  // namespace aura