The handler for ConfigureNotify events in the EGL X11 winsys was
incorrectly trying dereference the onscreen pointer even if it didn't
find an onscreen for the X window that has resized. This meant that if
the application has other windows that weren't created by Cogl then it
would crash when handling events for them.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit a0056df61903d74180d4e4caa1046e68396d1be0)
1455561a20