shell: Add implementation of fullscreen.

Undo fullscreen in shell_unset_fullscreen(), do all the stacking order
in shell_stack_fullscreen(), and configure black surface, method in
shell_configure_fullscreen().

Signed-off-by: Alex Wu <zhiwen.wu@linux.intel.com>
Signed-off-by: Juan Zhao <juan.j.zhao@linux.intel.com>
1 file changed