From bd70a73d43ce71faff424bb692e339f55f335713 Mon Sep 17 00:00:00 2001
From: Travis Grathwell <tgrathwell@pivotal.io>
Date: Fri, 31 Mar 2017 15:31:04 -0700
Subject: [PATCH] ios: Patch cancelAnimationFrame whenever
 fakeRequestAnimationFrame is used

The existing implementation of fakeRequestAnimationFrame
did not return a timer ID, so the frame could not be cancelled
if you wanted to cancel it. But if you do want to cancel it,
it needs to be cancelled through clearTimeout instead of
cancelAnimationFrame, because the timer IDs are different.

Signed-off-by: Jonathan Barnes <jbarnes@pivotal.io>
---
 src/shared/compatibility.js | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/shared/compatibility.js b/src/shared/compatibility.js
index 3f727a5c3..90e1165af 100644
--- a/src/shared/compatibility.js
+++ b/src/shared/compatibility.js
@@ -643,8 +643,13 @@ PDFJS.compatibilityChecked = true;
 
 // Support: IE<10, Android<4.0, iOS
 (function checkRequestAnimationFrame() {
-  function fakeRequestAnimationFrame(callback) {
-    window.setTimeout(callback, 20);
+  function installFakeAnimationFrameFunctions() {
+    window.requestAnimationFrame = function (callback) {
+      return window.setTimeout(callback, 20);
+    };
+    window.cancelAnimationFrame = function (timeoutID) {
+      window.clearTimeout(timeoutID);
+    };
   }
 
   if (!hasDOM) {
@@ -652,7 +657,7 @@ PDFJS.compatibilityChecked = true;
   }
   if (isIOS) {
     // requestAnimationFrame on iOS is broken, replacing with fake one.
-    window.requestAnimationFrame = fakeRequestAnimationFrame;
+    installFakeAnimationFrameFunctions();
     return;
   }
   if ('requestAnimationFrame' in window) {
@@ -660,8 +665,10 @@ PDFJS.compatibilityChecked = true;
   }
   window.requestAnimationFrame =
     window.mozRequestAnimationFrame ||
-    window.webkitRequestAnimationFrame ||
-    fakeRequestAnimationFrame;
+    window.webkitRequestAnimationFrame;
+  if (!('requestAnimationFrame' in window)) {
+    installFakeAnimationFrameFunctions();
+  }
 })();
 
 // Support: Android, iOS