From 9c817ce20c8aafe0e75bf3bd03dd6e57bd00db0a Mon Sep 17 00:00:00 2001
From: Joey Parrish <joeyparrish@google.com>
Date: Wed, 27 Jan 2016 08:11:08 -0800
Subject: [PATCH] Ignore spurious updateend events on IE11

Issue #251

Change-Id: Ifd4375a40795adb7f514f0a89383a1825361dae0
---
 lib/media/source_buffer_manager.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/media/source_buffer_manager.js b/lib/media/source_buffer_manager.js
index 72d8b21db6..f91666d8b8 100644
--- a/lib/media/source_buffer_manager.js
+++ b/lib/media/source_buffer_manager.js
@@ -647,7 +647,11 @@ shaka.media.SourceBufferManager.prototype.onSourceBufferUpdateEnd_ =
   shaka.log.v1(this.logPrefix_(), 'onSourceBufferUpdateEnd_');
 
   shaka.asserts.assert(!this.sourceBuffer_.updating);
-  shaka.asserts.assert(this.operationPromise_);
+  if (!this.operationPromise_) {
+    // Spurious event, which seems to happen on IE11 with rapid seeking.
+    // Ignore.
+    return;
+  }
 
   this.operationPromise_.resolve();
   this.operationPromise_ = null;