diff --git a/closure.log b/closure.log
new file mode 100644
index 0000000000..c442555558
--- /dev/null
+++ b/closure.log
@@ -0,0 +1,29 @@
+gulp-google-closure-compiler: polymer.html_script_13.js:621: WARNING - Invalid type for parameter 4 of function processElementStyles.
+Expected : string
+Found    : (string|undefined)
+More details:
+The found type is a union that includes an unexpected type: undefined
+          processElementStyles(this, template, is, ext, baseURI);
+                                                   ^^^
+
+polymer.html_script_6.js:36: WARNING - Type annotation references non-existent type array.
+     * @return {array} Array of contained <style> elements
+                ^^^^^
+
+polymer.html_script_6.js:56: WARNING - Type annotation references non-existent type array.
+     * @return {array} Array of contained styles.
+                ^^^^^
+
+polymer.html_script_6.js:85: WARNING - Type annotation references non-existent type array.
+     * @return {array} Array of styles
+                ^^^^^
+
+polymer.html_script_6.js:119: WARNING - Type annotation references non-existent type array.
+     * @return {array} Array of contained styles.
+                ^^^^^
+
+polymer.html_script_6.js:131: WARNING - Type annotation references non-existent type array.
+     * @return {array} Array of contained styles
+                ^^^^^
+
+0 error(s), 6 warning(s), 77.7% typed
diff --git a/lib/utils/style-gather.html b/lib/utils/style-gather.html
index 62694530e0..c0f9632c4d 100644
--- a/lib/utils/style-gather.html
+++ b/lib/utils/style-gather.html
@@ -15,7 +15,6 @@
   const MODULE_STYLE_LINK_SELECTOR = 'link[rel=import][type~=css]';
   const INCLUDE_ATTR = 'include';
   const SHADY_UNSCOPED_ATTR = 'shady-unscoped';
-  const unscopedStyleImportsMap = new WeakMap();
 
   function importModule(moduleId) {
     const /** Polymer.DomModule */ PolymerDomModule = customElements.get('dom-module');
@@ -92,6 +91,7 @@
      *
      * @memberof Polymer.StyleGather
      * @param {HTMLTemplateElement} template Template to gather styles from
+     * @param {string} baseURI baseURI for style content
      * @return {array} Array of styles
      * @this {StyleGather}
      */