Move event polling into CoglRenderer

This updates the cogl_poll_ apis to allow dispatching events before we
have a CoglContext and to also enables pollfd state to be changed in a
more add-hoc way by different Cogl components by replacing the
winsys->get_poll_info with _cogl_poll_renderer_add/remove_fd functions
and a winsys->get_dispatch_timeout vfunc.

One of the intentions here is that applications should be able to run
their mainloop before creating a CoglContext to potentially get events
relating to CoglOutputs.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 667e58c9cb2662aef5f44e580a9eda42dc8d0176)

cogl/cogl-glib-source.h

@@ -40,11 +40,21 @@ G_BEGIN_DECLS
  *
  * Creates a #GSource which handles Cogl's internal system event
  * processing. This can be used as a convenience instead of
- * cogl_poll_get_info() and cogl_poll_dispatch() in applications that
- * are already using the GLib main loop. After this is called the
- * #GSource should be attached to the main loop using
+ * cogl_poll_renderer_get_info() and cogl_poll_renderer_dispatch() in
+ * applications that are already using the GLib main loop. After this
+ * is called the #GSource should be attached to the main loop using
  * g_source_attach().
  *
+ * Applications that manually connect to a #CoglRenderer before they
+ * create a #CoglContext should instead use
+ * cogl_glib_renderer_source_new() so that events may be dispatched
+ * before a context has been created. In that case you don't need to
+ * use this api in addition later, it is simply enough to use
+ * cogl_glib_renderer_source_new() instead.
+ *
+ * <note>This api is actually just a thin convenience wrapper around
+ * cogl_glib_renderer_source_new()</note>
+ *
  * Return value: a new #GSource
  *
  * Stability: unstable
@@ -54,6 +64,27 @@ GSource *
 cogl_glib_source_new (CoglContext *context,
                       int priority);
 
+/**
+ * cogl_glib_renderer_source_new:
+ * @context: A #CoglContext
+ * @priority: The priority of the #GSource
+ *
+ * Creates a #GSource which handles Cogl's internal system event
+ * processing. This can be used as a convenience instead of
+ * cogl_poll_renderer_get_info() and cogl_poll_renderer_dispatch() in
+ * applications that are already using the GLib main loop. After this
+ * is called the #GSource should be attached to the main loop using
+ * g_source_attach().
+ *
+ * Return value: a new #GSource
+ *
+ * Stability: unstable
+ * Since: 1.16
+ */
+GSource *
+cogl_glib_renderer_source_new (CoglRenderer *renderer,
+                               int priority);
+
 G_END_DECLS
 
 #endif /* __COGL_GSOURCE_H__ */