Fix lint, update types

Author: kevinpschaaf

test/unit/debounce.html

@@ -214,7 +214,6 @@
 
     const testEnqueue = (shouldFlush, done) => {
       const actualOrder = [];
-      let i=1;
       const enqueue = (type, {db, cb} = {}) => {
         cb = cb || (() => actualOrder.push(cb));
         db = Polymer.Debouncer.debounce(db, type, cb);

types/lib/utils/debounce.d.ts

@@ -68,6 +68,11 @@ declare namespace Polymer {
      */
     cancel(): void;
 
+    /**
+     * Cancels a debouncer's async callback.
+     */
+    _cancelAsync(): void;
+
     /**
      * Flushes an active debouncer and returns a reference to itself.
      */