Check for NULL NativeView in linux/mac Screen::GetDisplayNearestWindow().

ui/views/widget/desktop_aura/desktop_screen_x11.cc

Index: ui/views/widget/desktop_aura/desktop_screen_x11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_screen_x11.cc b/ui/views/widget/desktop_aura/desktop_screen_x11.cc
index f4c03da817d894d4438eadaec81f3d05f96ad96c..bb253cff17ce48e6295bbee89574a874f5733462 100644
--- a/ui/views/widget/desktop_aura/desktop_screen_x11.cc
+++ b/ui/views/widget/desktop_aura/desktop_screen_x11.cc
@@ -157,6 +157,9 @@ std::vector<gfx::Display> DesktopScreenX11::GetAllDisplays() const {
 
 gfx::Display DesktopScreenX11::GetDisplayNearestWindow(
     gfx::NativeView window) const {
+  if (!window)
+    return GetPrimaryDisplay();
+
   // Getting screen bounds here safely is hard.
   //
   // You'd think we'd be able to just call window->GetBoundsInScreen(), but we