Add missing required(boolean) method to $mdDialog PromptConfig
@@ -393,6 +393,11 @@ md.$dialog.PromptConfig_.prototype.parent = function(parent) {};
*/
md.$dialog.PromptConfig_.prototype.css = function(css) {};
+/**
+ * @param {boolean} required
+ * @return {!md.$dialog.PromptConfig_}
+ */
+md.$dialog.PromptConfig_.prototype.required = function(required) {};
/** @typedef {!md.$dialog.options|!md.$dialog.ConfirmConfig_|
* !md.$dialog.AlertConfig_|!md.$dialog.PromptConfig_} */
