[geary/mjog/attachment-download-dir] Application.AttachmentManager: Default save chooser to XDG_DOWNLOADS

[Michael Gratton <mjog src gnome org>]

commit 2b5ef5ea522538c1db959f2faed422cfdccc037c
Author: Michael Gratton <mike vee net>
Date:   Wed Feb 3 08:46:03 2021 +1100

    Application.AttachmentManager: Default save chooser to XDG_DOWNLOADS
    
    We know that location is writable under Flatpak at the moment, so
    default to it.

 src/client/application/application-attachment-manager.vala | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/src/client/application/application-attachment-manager.vala 
b/src/client/application/application-attachment-manager.vala
index f4b5eb067..aa8cb1b47 100644
--- a/src/client/application/application-attachment-manager.vala
+++ b/src/client/application/application-attachment-manager.vala
@@ -271,6 +271,10 @@ public class Application.AttachmentManager : GLib.Object {
             Stock._SAVE,
             Stock._CANCEL
         );
+        var download_dir = GLib.Environment.get_user_special_dir(DOWNLOAD);
+        if (!Geary.String.is_empty_or_whitespace(download_dir)) {
+            dialog.set_current_folder(download_dir);
+        }
         dialog.set_local_only(false);
         return dialog;
     }