Enable hidpi on Linux, refactor a bit on Windows to share

ui/views/widget/desktop_aura/desktop_native_widget_aura.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/views/widget/desktop_aura/desktop_native_widget_aura.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/cursor_client.h"
@@ skipping 43 matching lines @@
 #include "ui/wm/core/native_cursor_manager.h"
 #include "ui/wm/core/shadow_controller.h"
 #include "ui/wm/core/shadow_types.h"
 #include "ui/wm/core/visibility_controller.h"
 #include "ui/wm/core/window_modality_controller.h"
 #include "ui/wm/public/activation_client.h"
 #include "ui/wm/public/drag_drop_client.h"
 
 #if defined(OS_WIN)
 #include "ui/base/win/shell.h"
-#include "ui/gfx/win/dpi.h"
 #endif
 
 DECLARE_EXPORTED_WINDOW_PROPERTY_TYPE(VIEWS_EXPORT,
                                       views::DesktopNativeWidgetAura*);
 
 namespace views {
 
 DEFINE_WINDOW_PROPERTY_KEY(DesktopNativeWidgetAura*,
                            kDesktopNativeWidgetAuraKey, NULL);
 
@@ skipping 1136 matching lines @@
   if (cursor_reference_count_ == 0) {
     // We are the last DesktopNativeWidgetAura instance, and we are responsible
     // for cleaning up |cursor_manager_|.
     delete cursor_manager_;
     native_cursor_manager_ = NULL;
     cursor_manager_ = NULL;
   }
 }
 
 }  // namespace views