Add a crash for debugging when we get into a bad state.

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.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_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_X11_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_X11_H_
 
 #include <stddef.h>
 #include <stdint.h>
 #include <X11/extensions/shape.h>
@@ skipping 241 matching lines @@
   ::Window xwindow_;
 
   // The native root window.
   ::Window x_root_window_;
 
   ui::X11AtomCache atom_cache_;
 
   // Is the window mapped to the screen?
   bool window_mapped_;
 
+  // Keeps track of whether we have ever mapped/withdrawn this
+  // window. Debugging information in trying to track down crbug.com/381732.
+  bool x_map_window_was_called_ = false;
+
   // The bounds of |xwindow_|.
   gfx::Rect bounds_in_pixels_;
 
   // Whenever the bounds are set, we keep the previous set of bounds around so
   // we can have a better chance of getting the real
   // |restored_bounds_in_pixels_|. Window managers tend to send a Configure
   // message with the maximized bounds, and then set the window maximized
   // property. (We don't rely on this for when we request that the window be
   // maximized, only when we detect that some other process has requested that
   // we become the maximized window.)
@@ skipping 77 matching lines @@
   base::CancelableCallback<void()> delayed_resize_task_;
 
   base::WeakPtrFactory<DesktopWindowTreeHostX11> close_widget_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopWindowTreeHostX11);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_X11_H_