[Video module]: handle resize from ui

in vlc/include/vlc_vout_window.h

/**                                                                                                                                                                       
 * Reports the current window size.                                                                                                                                       
 *                                                                                                                                                                        
 * This function is called by the window implementation and notifies the owner                                                                                            
 * of the window what the pixel dimensions of the window are (or should be,                                                                                               
 * depending on the windowing system).                                                                                                                                    
 *                                                                                                                                                                        
 * \note This function is thread-safe. In case of concurrent call, it is                                                                                                  
 * undefined which one is taken into account (but at least one is).                                                                                                       
 */
static inline void vout_window_ReportSize(vout_window_t *window,
                                          unsigned width, unsigned height)