Added spinner for resynck

Added spinner for resynck. Added stack with button and spinner. After
pushing the button button will be replaced witn spinning spinner
indicating process. Spinner will be replaced with button after receiving
message from server.

!Sometimes spinner will stop to spin, but the process will still be
running. You can start animation again by pressing on the spinner. It is
known issue with gtk spinner

main/src/ui/contact_details/history_provider.vala

@@ -28,9 +28,21 @@ public class HistoryProvider : Plugins.ContactDetailsProvider, Object {
         entity_info.has_feature.begin(conversation.account, conversation.counterpart, Xmpp.MessageArchiveManagement.NS_URI, (_, res) => {
             bool can_do_mam = entity_info.has_feature.end(res);
             if (can_do_mam) {
+
                 Button resync_button = new Button.with_label(RESYNC_LABEL);
-                contact_details.add("Permissions", RESYNC_DESC_LABEL, "", resync_button);
+                Stack resync_stack = new Stack();
+                Gtk.Spinner spinner = new Gtk.Spinner();
+
+                resync_stack.visible = true;
+                contact_details.add("Permissions", RESYNC_DESC_LABEL, "", resync_stack);
+                resync_stack.add_child(spinner);
+                resync_stack.add_child(resync_button);
+                resync_stack.set_visible_child(resync_button);
+
                 resync_button.clicked.connect(() => {
+                    resync_stack.set_visible_child(spinner);
+                    spinner.start();
+
                     if (!sync_cancellables.has_key(conversation.account)) {
                         sync_cancellables[conversation.account] = new HashMap<Jid, Cancellable>();
                     }
@@ -40,6 +52,8 @@ public class HistoryProvider : Plugins.ContactDetailsProvider, Object {
                         var history_sync = stream_interactor.get_module(MessageProcessor.IDENTITY).history_sync;
                         history_sync.fetch_history.begin(conversation.account, conversation.counterpart.bare_jid, sync_cancellables[conversation.account][conversation.counterpart.bare_jid], (_, res) => {
                             history_sync.fetch_everything.end(res);
+                            spinner.stop();
+                            resync_stack.set_visible_child(resync_button);
                             sync_cancellables[conversation.account].unset(conversation.counterpart.bare_jid);
                         });
                     }