If the video player tries to play an unknown type file, it will enter
the error_cb() function, which is called in another thread.
Use gdk_threads_enter/gdk_threads_leave to ensure the safe of gtk
multi-thread operation.
This fixes [BUGID #474]
Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Dongxiao Xu