Resolve display promise when all the rows of a tree view are displayed

Since changeset 82c4ec24b675, the tree is drawn asynchronously but some
methods may require the tree to be fully rendered to compute its values, so
the display method must return a promise that resolves when all of the rows
are displayed

issue5849
review33331002

src/view/tree.js

@@ -344,8 +344,7 @@
                 this.table.removeClass('responsive-header');
             }
 
-            this.redraw(selected, expanded);
-            return jQuery.when();
+            return this.redraw(selected, expanded);
         },
         construct: function(selected, expanded, extend) {
             var tbody = this.tbody;
@@ -377,7 +376,7 @@
             }
         },
         redraw: function(selected, expanded) {
-            redraw_async(this.rows, selected, expanded);
+            return redraw_async(this.rows, selected, expanded);
         },
         switch_: function(path) {
             this.screen.row_activate();
@@ -577,6 +576,7 @@
 
     function redraw_async(rows, selected, expanded) {
         var chunk = Sao.config.display_size;
+        var dfd = jQuery.Deferred();
         var redraw_rows = function(i) {
             rows.slice(i, i + chunk).forEach(function(row) {
                 row.redraw(selected, expanded);
@@ -584,9 +584,12 @@
             i += chunk;
             if (i < rows.length) {
                 setTimeout(redraw_rows, 0, i);
+            } else {
+                dfd.resolve();
             }
         };
         setTimeout(redraw_rows, 0, 0);
+        return dfd;
     }
 
     Sao.View.Tree.Row = Sao.class_(Object, {