Add a flag use_software_compositing to the Widget::InitParams structure.

ui/views/widget/widget.h

 // 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.
 
 #ifndef UI_VIEWS_WIDGET_WIDGET_H_
 #define UI_VIEWS_WIDGET_WIDGET_H_
 
 #include <set>
 #include <stack>
 #include <vector>
@@ skipping 248 matching lines @@
     gfx::NativeWindow context;
     // If true, forces the window to be shown in the taskbar, even for window
     // types that do not appear in the taskbar by default (popup and bubble).
     bool force_show_in_taskbar;
     // Only used by X11, for root level windows. Specifies the res_name and
     // res_class fields, respectively, of the WM_CLASS window property. Controls
     // window grouping and desktop file matching in Linux window managers.
     std::string wm_role_name;
     std::string wm_class_name;
     std::string wm_class_class;
+
+    // If true then the widget uses software compositing. Defaults to false.
+    // Only used on Windows.
+    bool force_software_compositing;
   };
 
   Widget();
   ~Widget() override;
 
   // Creates a toplevel window with no context. These methods should only be
   // used in cases where there is no contextual information because we're
   // creating a toplevel window connected to no other event.
   //
   // If you have any parenting or context information, or can pass that
@@ skipping 677 matching lines @@
   bool movement_disabled_;
 
   ScopedObserver<ui::NativeTheme, ui::NativeThemeObserver> observer_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(Widget);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_WIDGET_H_