From 44025a3ec12d5d9969a7c2ba1079ba1d196339e0 Mon Sep 17 00:00:00 2001
From: Rob Wu <rob@robwu.nl>
Date: Tue, 23 Jan 2018 20:12:03 +0100
Subject: [PATCH 1/2] Explicitly state intended support in compatibility.js

Add comments with supported browser versions where missing.

Method:
- Use MDN compat tables if available.
- Otherwise test in Chrome (31+) otherwise.
  (the Chrome Web Store does not update older versions of
   Chrome, so probably nobody is interested in even older
   versions, even though there is an existing comment for
   Chrome<29 at `document.currentScript`).
---
 src/shared/compatibility.js | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/shared/compatibility.js b/src/shared/compatibility.js
index 742d3aa85..a12e93bda 100644
--- a/src/shared/compatibility.js
+++ b/src/shared/compatibility.js
@@ -75,6 +75,7 @@ PDFJS.compatibilityChecked = true;
 })();
 
 // Checks if navigator.language is supported
+// Support: IE<11
 (function checkNavigatorLanguage() {
   if (typeof navigator === 'undefined') {
     return;
@@ -151,7 +152,7 @@ PDFJS.compatibilityChecked = true;
 })();
 
 // Provides support for Object.values in legacy browsers.
-// Support: IE.
+// Support: IE, Chrome<54
 (function checkObjectValues() {
   if (Object.values) {
     return;
@@ -160,7 +161,7 @@ PDFJS.compatibilityChecked = true;
 })();
 
 // Provides support for Array.prototype.includes in legacy browsers.
-// Support: IE.
+// Support: IE, Chrome<47
 (function checkArrayIncludes() {
   if (Array.prototype.includes) {
     return;
@@ -169,7 +170,7 @@ PDFJS.compatibilityChecked = true;
 })();
 
 // Provides support for Math.log2 in legacy browsers.
-// Support: IE.
+// Support: IE, Chrome<38
 (function checkMathLog2() {
   if (Math.log2) {
     return;
@@ -187,7 +188,7 @@ PDFJS.compatibilityChecked = true;
 })();
 
 // Provides support for Number.isInteger in legacy browsers.
-// Support: IE.
+// Support: IE, Chrome<34
 (function checkNumberIsInteger() {
   if (Number.isInteger) {
     return;
@@ -195,6 +196,7 @@ PDFJS.compatibilityChecked = true;
   Number.isInteger = require('core-js/fn/number/is-integer');
 })();
 
+// Support: IE, Safari<8, Chrome<32
 (function checkPromise() {
   if (globalScope.Promise) {
     return;
@@ -202,6 +204,7 @@ PDFJS.compatibilityChecked = true;
   globalScope.Promise = require('core-js/fn/promise');
 })();
 
+// Support: IE<11, Safari<8, Chrome<36
 (function checkWeakMap() {
   if (globalScope.WeakMap) {
     return;
@@ -209,6 +212,7 @@ PDFJS.compatibilityChecked = true;
   globalScope.WeakMap = require('core-js/fn/weak-map');
 })();
 
+// Support: IE, Chrome<32
 // Polyfill from https://github.com/Polymer/URL
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */

From 5d1c541702bd608d476d62bd4de051bb9b8d6171 Mon Sep 17 00:00:00 2001
From: Rob Wu <rob@robwu.nl>
Date: Fri, 26 Jan 2018 12:18:57 +0100
Subject: [PATCH 2/2] Enable some polyfills for compat with Chrome 49

Successfully tested with Chrome 49.
---
 src/shared/compatibility.js    | 28 ++++++++++++++++++----------
 src/shared/streams_polyfill.js |  3 ---
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/src/shared/compatibility.js b/src/shared/compatibility.js
index a12e93bda..57d9c47c7 100644
--- a/src/shared/compatibility.js
+++ b/src/shared/compatibility.js
@@ -18,10 +18,16 @@
 // Skip compatibility checks for the extensions and if we already ran
 // this module.
 if ((typeof PDFJSDev === 'undefined' ||
-     !PDFJSDev.test('FIREFOX || MOZCENTRAL || CHROME')) &&
+     !PDFJSDev.test('FIREFOX || MOZCENTRAL')) &&
     (typeof PDFJS === 'undefined' || !PDFJS.compatibilityChecked)) {
 
+// In the Chrome extension, most of the polyfills are unnecessary.
+// We support down to Chrome 49, because it's still commonly used by Windows XP
+// users - https://github.com/mozilla/pdf.js/issues/9397
+if (typeof PDFJSDev === 'undefined' || !PDFJSDev.test('CHROME')) {
+
 var globalScope = require('./global_scope');
+
 const isNodeJS = require('./is_node');
 
 var userAgent = (typeof navigator !== 'undefined' && navigator.userAgent) || '';
@@ -151,15 +157,6 @@ PDFJS.compatibilityChecked = true;
   };
 })();
 
-// Provides support for Object.values in legacy browsers.
-// Support: IE, Chrome<54
-(function checkObjectValues() {
-  if (Object.values) {
-    return;
-  }
-  Object.values = require('core-js/fn/object/values');
-})();
-
 // Provides support for Array.prototype.includes in legacy browsers.
 // Support: IE, Chrome<47
 (function checkArrayIncludes() {
@@ -865,4 +862,15 @@ PDFJS.compatibilityChecked = true;
   globalScope.URL = JURL;
 })();
 
+} // End of !PDFJSDev.test('CHROME')
+
+// Provides support for Object.values in legacy browsers.
+// Support: IE, Chrome<54
+(function checkObjectValues() {
+  if (Object.values) {
+    return;
+  }
+  Object.values = require('core-js/fn/object/values');
+})();
+
 }
diff --git a/src/shared/streams_polyfill.js b/src/shared/streams_polyfill.js
index e35da6cd9..7c8e85d87 100644
--- a/src/shared/streams_polyfill.js
+++ b/src/shared/streams_polyfill.js
@@ -31,9 +31,6 @@ if (typeof ReadableStream !== 'undefined') {
 if (isReadableStreamSupported) {
   exports.ReadableStream = ReadableStream;
 } else {
-  if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('CHROME')) {
-    throw new Error('ReadableStream polyfill is not found for Chrome bundle');
-  }
   exports.ReadableStream =
     require('../../external/streams/streams-lib').ReadableStream;
 }