[IMP] web_editor: lazy load the wysiwyg

Issue: wysiwyg asset slow down the loading of the website, error
inadvertently introduced: https://github.com/odoo/odoo/pull/29775

The assets are now loaded assynchroneously, when the editor is needed,
its assets will be loaded.

closes odoo/odoo#30700

2 files changed, 33 insertions, 14 deletions

diff --git a/addons/web/static/src/js/core/widget.js b/addons/web/static/src/js/core/widget.js
index b25cd99587b..d3b9cc1033c 100644
--- a/addons/web/static/src/js/core/widget.js
+++ b/addons/web/static/src/js/core/widget.js
@@ -84,6 +84,32 @@ var Widget = core.Class.extend(mixins.PropertiesMixin, ServicesMixin, {
      * @type {null|string[]}
      */
     xmlDependencies: null,
+    /**
+     * List of paths to css files that need to be loaded before the widget can
+     * be rendered. This will not induce loading anything that has already been
+     * loaded.
+     *
+     * @type {null|string[]}
+     */
+    cssLibs: null,
+    /**
+     * List of paths to js files that need to be loaded before the widget can
+     * be rendered. This will not induce loading anything that has already been
+     * loaded.
+     *
+     * @type {null|string[]}
+     */
+    jsLibs: null,
+    /**
+     * List of xmlID that need to be loaded before the widget can be rendered.
+     * The content css (link file or style tag) and js (file or inline) of the
+     * assets are loaded.
+     * This will not induce loading anything that has already been
+     * loaded.
+     *
+     * @type {null|string[]}
+     */
+    assetLibs: null,
 
     /**
      * Constructs the widget and sets its parent if a parent is given.
@@ -115,13 +141,16 @@ var Widget = core.Class.extend(mixins.PropertiesMixin, ServicesMixin, {
      * @returns {Deferred}
      */
     willStart: function () {
+        var defs = [];
         if (this.xmlDependencies) {
-            var defs = _.map(this.xmlDependencies, function (xmlPath) {
+            defs.push.apply(defs, _.map(this.xmlDependencies, function (xmlPath) {
                 return ajax.loadXML(xmlPath, core.qweb);
-            });
-            return $.when.apply($, defs);
+            }));
         }
-        return $.when();
+        if (this.jsLibs || this.cssLibs || this.assetLibs) {
+            defs.push(ajax.loadLibs(this));
+        }
+        return $.when.apply($, defs);
     },
     /**
      * Method called after rendering. Mostly used to bind actions, perform
diff --git a/addons/web/static/src/js/fields/abstract_field.js b/addons/web/static/src/js/fields/abstract_field.js
index 37d2f22ef55..edc7c03ac02 100644
--- a/addons/web/static/src/js/fields/abstract_field.js
+++ b/addons/web/static/src/js/fields/abstract_field.js
@@ -35,8 +35,6 @@ var field_utils = require('web.field_utils');
 var Widget = require('web.Widget');
 
 var AbstractField = Widget.extend({
-    cssLibs: [],
-    jsLibs: [],
     events: {
         'keydown': '_onKeydown',
     },
@@ -183,14 +181,6 @@ var AbstractField = Widget.extend({
         }
     },
     /**
-     * Loads the libraries listed in this.jsLibs and this.cssLibs
-     *
-     * @override
-     */
-    willStart: function () {
-        return $.when(ajax.loadLibs(this), this._super.apply(this, arguments));
-    },
-    /**
      * When a field widget is appended to the DOM, its start method is called,
      * and will automatically call render. Most widgets should not override this.
      *