Make browser windows override_redirect when dragging tabs.

ui/aura/window_tree_host_x11.cc

Index: ui/aura/window_tree_host_x11.cc
diff --git a/ui/aura/window_tree_host_x11.cc b/ui/aura/window_tree_host_x11.cc
index 084296c34086b8ab8e2c9a20912036b04dedf0be..a183f93f5fc63044e5f1027d4deea4fe7fb2af83 100644
--- a/ui/aura/window_tree_host_x11.cc
+++ b/ui/aura/window_tree_host_x11.cc
@@ -551,6 +551,10 @@ void WindowTreeHostX11::SetCapture() {
 void WindowTreeHostX11::ReleaseCapture() {
 }
 
+void WindowTreeHostX11::RemapAsNormalWindow() {
+  NOTREACHED();
+}
+
 void WindowTreeHostX11::SetCursorNative(gfx::NativeCursor cursor) {
   if (cursor == current_cursor_)
     return;