From 4fc64ceb76162d01d9ec38a869a7a96f9b13a4f2 Mon Sep 17 00:00:00 2001
From: Daniel Johnson <danielj@ifixit.com>
Date: Fri, 17 Feb 2017 17:15:40 -0800
Subject: [PATCH] iOS Chrome: Fix broken download button

The download button in pdf.js doesn't work in iOS Chrome.

  - It appears to be an issue with URLs from URL.createObjectURL.
    The URL is correct, but iOS Chrome won't even load the URL
    when `a.click()` is called in `download_manager.js`. Even
    if you manually visit the URL, you get a blank page.

  - Fix this by detecting iOS Chrome and disabling createObjectURL.

The `download_manager.js` `download` method wasn't checking
`PDFJS.disableCreateObjectURL`, so check it there, too.

  - Move the navigator.msSaveBlob check earlier, so that
    this doesn't change IE10 / IE11 behavior.

  - Remove the !URL check since pdf.js has a URL polyfill
    now.
---
 web/compatibility.js    |  8 +++++---
 web/download_manager.js | 12 ++++++------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/web/compatibility.js b/web/compatibility.js
index 2b4fe85f4..4bed22d79 100644
--- a/web/compatibility.js
+++ b/web/compatibility.js
@@ -26,6 +26,7 @@ var isAndroidPre3 = /Android\s[0-2][^\d]/.test(userAgent);
 var isAndroidPre5 = /Android\s[0-4][^\d]/.test(userAgent);
 var isChrome = userAgent.indexOf('Chrom') >= 0;
 var isChromeWithRangeBug = /Chrome\/(39|40)\./.test(userAgent);
+var isIOSChrome = userAgent.indexOf('CriOS') >= 0;
 var isIE = userAgent.indexOf('Trident') >= 0;
 var isIOS = /\b(iPad|iPhone|iPod)(?=;)/.test(userAgent);
 var isOpera = userAgent.indexOf('Opera') >= 0;
@@ -456,10 +457,11 @@ if (typeof PDFJS === 'undefined') {
 })();
 
 // Checks if possible to use URL.createObjectURL()
-// Support: IE
+// Support: IE, Chrome on iOS
 (function checkOnBlobSupport() {
-  // sometimes IE loosing the data created with createObjectURL(), see #3977
-  if (isIE) {
+  // sometimes IE and Chrome on iOS loosing the data created with
+  // createObjectURL(), see #3977 and #8081
+  if (isIE || isIOSChrome) {
     PDFJS.disableCreateObjectURL = true;
   }
 })();
diff --git a/web/download_manager.js b/web/download_manager.js
index 674dfb622..0be8a011b 100644
--- a/web/download_manager.js
+++ b/web/download_manager.js
@@ -86,12 +86,6 @@ if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC || CHROME')) {
     },
 
     download: function DownloadManager_download(blob, url, filename) {
-      if (!URL) {
-        // URL.createObjectURL is not supported
-        this.downloadUrl(url, filename);
-        return;
-      }
-
       if (navigator.msSaveBlob) {
         // IE10 / IE11
         if (!navigator.msSaveBlob(blob, filename)) {
@@ -100,6 +94,12 @@ if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC || CHROME')) {
         return;
       }
 
+      if (pdfjsLib.PDFJS.disableCreateObjectURL) {
+        // URL.createObjectURL is not supported
+        this.downloadUrl(url, filename);
+        return;
+      }
+
       var blobUrl = URL.createObjectURL(blob);
       download(blobUrl, filename);
     }