[gtk+] Adapt to simplified file chooser portal api

[Matthias Clasen <matthiasc src gnome org>]

commit 2b77eaa1ae8ab835e42dd082375e406c6b4bd906
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jul 6 12:54:29 2016 -0400

    Adapt to simplified file chooser portal api
    
    OpenFiles is gone, just set the 'multiple' option instead.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=768499

 gtk/gtkfilechoosernativeportal.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkfilechoosernativeportal.c b/gtk/gtkfilechoosernativeportal.c
index a8e0fc7..8ff2a46 100644
--- a/gtk/gtkfilechoosernativeportal.c
+++ b/gtk/gtkfilechoosernativeportal.c
@@ -298,10 +298,8 @@ gtk_file_chooser_native_portal_show (GtkFileChooserNative *self)
   action = gtk_file_chooser_get_action (GTK_FILE_CHOOSER (self));
   multiple = gtk_file_chooser_get_select_multiple (GTK_FILE_CHOOSER (self));
 
-  if (action == GTK_FILE_CHOOSER_ACTION_OPEN && !multiple)
+  if (action == GTK_FILE_CHOOSER_ACTION_OPEN)
     method_name = "OpenFile";
-  else if (action == GTK_FILE_CHOOSER_ACTION_OPEN && multiple)
-    method_name = "OpenFiles";
   else if (action == GTK_FILE_CHOOSER_ACTION_SAVE)
     method_name = "SaveFile";
   else
@@ -345,6 +343,8 @@ gtk_file_chooser_native_portal_show (GtkFileChooserNative *self)
     }
 
   g_variant_builder_init (&opt_builder, G_VARIANT_TYPE_VARDICT);
+  g_variant_builder_add (&opt_builder, "{sv}", "multiple",
+                         g_variant_new_boolean (multiple));
   if (self->accept_label)
     g_variant_builder_add (&opt_builder, "{sv}", "accept_label",
                            g_variant_new_string (self->accept_label));