Make browser windows override_redirect when dragging tabs.

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 236fb0884bb753694f82dc9af222848015650eb5..bbeeb61b03b59ecffcab65a6362fd2f604a12284 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
@@ -1279,6 +1279,14 @@ void DesktopWindowTreeHostX11::InitX11Window(
   OnAcceleratedWidgetAvailable();
 }
 
+void DesktopWindowTreeHostX11::RemapAsNormalWindow() {
+  XUnmapWindow(xdisplay_, xwindow_);
+  XSetWindowAttributes swa;
+  swa.override_redirect = False;
+  XChangeWindowAttributes(xdisplay_, xwindow_, CWOverrideRedirect, &swa);
+  XMapWindow(xdisplay_, xwindow_);
+}
+
 gfx::Size DesktopWindowTreeHostX11::AdjustSize(
     const gfx::Size& requested_size_in_pixels) {
   std::vector<gfx::Display> displays =