[IMP] web_editor: make media widget save always return a Promise

Before this commit, the return value would be mixed. For consistency, make it
always return a Promise.

PR: #33509

addons/web_editor/static/src/js/wysiwyg/widgets/media.js

@@ -43,7 +43,7 @@ var MediaWidget = Widget.extend({
      * Saves the currently configured media on the target media.
      *
      * @abstract
-     * @returns {*}
+     * @returns {Promise}
      */
     save: function () {},
 
@@ -183,6 +183,9 @@ var FileWidget = SearchableMediaWidget.extend({
     //--------------------------------------------------------------------------
 
     /**
+     * Saves the currently selected image on the target media. If new files are
+     * currently being added, delays the save until all files have been added.
+     *
      * @override
      */
     save: function () {
@@ -398,17 +401,18 @@ var FileWidget = SearchableMediaWidget.extend({
     },
     /**
      * @private
+     * @returns {Promise}
      */
     _save: function () {
         var self = this;
 
         if (this.options.multiImages) {
-            return this.images;
+            return Promise.resolve(this.images);
         }
 
         var img = this.images[0];
         if (!img) {
-            return this.media;
+            return Promise.resolve(this.media);
         }
 
         var prom;
@@ -818,7 +822,7 @@ var IconWidget = SearchableMediaWidget.extend({
             class: _.compact(finalClasses).join(' '),
             style: style || null,
         });
-        return this.media;
+        return Promise.resolve(this.media);
     },
     /**
      * @override
@@ -976,7 +980,7 @@ var VideoWidget = MediaWidget.extend({
             );
             this.media = this.$media[0];
         }
-        return this.media;
+        return Promise.resolve(this.media);
     },
 
     //--------------------------------------------------------------------------

addons/web_editor/static/src/js/wysiwyg/widgets/media_dialog.js

@@ -167,7 +167,7 @@ var MediaDialog = Dialog.extend({
         var self = this;
         var _super = this._super;
         var args = arguments;
-        return Promise.resolve(this.activeWidget.save()).then(function (data) {
+        return this.activeWidget.save().then(function (data) {
             self.final_data = data;
             return _super.apply(self, args);
         });