Store GjsContext pointer in ShellGlobal

Future functionality in ShellGlobal needs access to the GjsContext.

https://bugzilla.gnome.org/show_bug.cgi?id=599561

src/gnome-shell-plugin.c

@@ -40,7 +40,7 @@
 
 #include "display.h"
 
-#include "shell-global.h"
+#include "shell-global-private.h"
 #include "shell-wm.h"
 
 static void gnome_shell_plugin_constructed (GObject *object);
@@ -192,6 +192,8 @@ gnome_shell_plugin_constructed (GObject *object)
   shell_plugin->gjs_context = gjs_context_new_with_search_path(search_path);
   g_strfreev(search_path);
 
+  _shell_global_set_gjs_context (shell_global_get (), shell_plugin->gjs_context);
+
   if (!gjs_context_eval (shell_plugin->gjs_context,
                          "const Main = imports.ui.main; Main.start();",
                          -1,