diff --git a/externs/webcomponents-externs.js b/externs/webcomponents-externs.js
index b773a92834..05bdd16a04 100644
--- a/externs/webcomponents-externs.js
+++ b/externs/webcomponents-externs.js
@@ -32,6 +32,7 @@ window.HTMLImports = HTMLImports;
 var ShadyDOM = {};
 
 ShadyDOM.inUse;
+ShadyDOM.composedPath;
 
 ShadyDOM.flush = function() {};
 
diff --git a/lib/utils/boot.js b/lib/utils/boot.js
index d2bce39263..5e726bbd9f 100644
--- a/lib/utils/boot.js
+++ b/lib/utils/boot.js
@@ -13,8 +13,8 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
  * When using Closure Compiler, JSCompiler_renameProperty(property, object) is replaced by the munged name for object[property]
  * We cannot alias this function, so we have to use a small shim that has the same behavior when not compiling.
  *
- * @param {string} prop Property name
- * @param {?Object} obj Reference object
+ * @param {?} prop Property name
+ * @param {*} obj Reference object
  * @return {string} Potentially renamed property name
  */
 window.JSCompiler_renameProperty = function(prop, obj) {