Add shell_interface type.

Signed-off-by: Chris Michael <cp.michael@samsung.com>

src/bin/e_wayland/e_shell.h

@@ -1,8 +1,18 @@
 #ifdef E_TYPEDEFS
+
+typedef struct _E_Shell_Interface E_Shell_Interface;
+
 #else
 # ifndef E_SHELL_H
 #  define E_SHELL_H
 
+struct _E_Shell_Interface
+{
+   void *shell;
+
+   /* TODO: surface_create */
+};
+
 EINTERN int e_shell_init(void);
 EINTERN int e_shell_shutdown(void);