function startEditing(inplaceEditor)
    {
        var controller = /** @type {!WebInspector.InplaceEditor} */ (inplaceEditor).startEditing(element, config);
        if (!controller)
            return Promise.reject(new Error("Editing is already in progress"));
        return controller;
    }
@param {!Object} inplaceEditor
@return {!WebInspector.InplaceEditor.Controller|!Promise.<!WebInspector.InplaceEditor.Controller>}