Only update icon if the new one is not null.

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
index 125e8f0c1551fead63dc6ec4544f48b58438b6f6..fa7c5917d450f3671dbab7e9c8f602418d730e8f 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
@@ -793,9 +793,7 @@ void DesktopWindowTreeHostX11::SetWindowIcons(
   if (app_icon.HasRepresentation(1.0f))
     SerializeImageRepresentation(app_icon.GetRepresentation(1.0f), &data);
 
-  if (data.empty())
-    XDeleteProperty(xdisplay_, xwindow_, atom_cache_.GetAtom("_NET_WM_ICON"));
-  else
+  if (!data.empty())
     ui::SetAtomArrayProperty(xwindow_, "_NET_WM_ICON", "CARDINAL", data);
 }