manager: Move GOA to GcalContext

Another step into making GcalManager only be responsible
for handling backend interactions.

src/gcal-context.h

@@ -25,6 +25,7 @@
 #include "weather/gcal-weather-service.h"
 
 #include <glib-object.h>
+#include <goa/goa.h>
 
 G_BEGIN_DECLS
 
@@ -35,6 +36,8 @@ GcalContext*         gcal_context_new                            (void);
 
 GcalClock*           gcal_context_get_clock                      (GcalContext        *self);
 
+GoaClient*           gcal_context_get_goa_client                 (GcalContext        *self);
+
 GcalManager*         gcal_context_get_manager                    (GcalContext        *self);
 
 GSettings*           gcal_context_get_settings                   (GcalContext        *self);