Bump to v4.17.5.

_safeGet.js

@@ -0,0 +1,21 @@
+define([], function() {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /**
+   * Gets the value at `key`, unless `key` is "__proto__".
+   *
+   * @private
+   * @param {Object} object The object to query.
+   * @param {string} key The key of the property to get.
+   * @returns {*} Returns the property value.
+   */
+  function safeGet(object, key) {
+    return key == '__proto__'
+      ? undefined
+      : object[key];
+  }
+
+  return safeGet;
+});