From 631e6bebff553ce42c278cb7b670ab160207656a Mon Sep 17 00:00:00 2001
From: Yury Delendik <ydelendik@mozilla.com>
Date: Tue, 13 Jun 2017 09:16:12 -0500
Subject: [PATCH] Fixes WeakMap polyfill (and improves PDFWorker port check).

---
 src/display/api.js          | 2 +-
 src/shared/compatibility.js | 8 ++++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/display/api.js b/src/display/api.js
index 729b6276487f2..e7757ddbb87b8 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -1232,7 +1232,7 @@ var PDFWorker = (function PDFWorkerClosure() {
   let pdfWorkerPorts = new WeakMap();
 
   function PDFWorker(name, port) {
-    if (pdfWorkerPorts.has(port)) {
+    if (port && pdfWorkerPorts.has(port)) {
       throw new Error('Cannot use more than one PDFWorker per port');
     }
 
diff --git a/src/shared/compatibility.js b/src/shared/compatibility.js
index 0af66a21e727d..67f332c7e6f8e 100644
--- a/src/shared/compatibility.js
+++ b/src/shared/compatibility.js
@@ -1176,10 +1176,14 @@ PDFJS.compatibilityChecked = true;
   }
   WeakMap.prototype = {
     has(obj) {
+      if ((typeof obj !== 'object' && typeof obj !== 'function') ||
+          obj === null) {
+        return false;
+      }
       return !!Object.getOwnPropertyDescriptor(obj, this.id);
     },
-    get(obj, defaultValue) {
-      return this.has(obj) ? obj[this.id] : defaultValue;
+    get(obj) {
+      return this.has(obj) ? obj[this.id] : undefined;
     },
     set(obj, value) {
       Object.defineProperty(obj, this.id, {