function computeDescriptors(textRange)
        {
            if (!textRange)
                return [];
            var propertyName = textEditor.copyRange(textRange);
            var descriptors = catalog.itemDescriptors(propertyName);
            if (descriptors.length)
                return descriptors;
            if (propertyName.toUpperCase() !== propertyName || !previousTokenText || !window[previousTokenText] || !window[previousTokenText][propertyName])
                return [];
            return catalog.constantDescriptors(previousTokenText);
        }
@param {?WebInspector.TextRange} textRange
@return {!Array.<!WebInspector.DocumentationCatalog.ItemDescriptor>}