From 2d76d6ff74b046d3cc268be6bcaf327bde5ec912 Mon Sep 17 00:00:00 2001
From: Gabriel Majoulet <gmajoulet@gmail.com>
Date: Tue, 24 Mar 2020 11:00:02 -0400
Subject: [PATCH] Fix progress bar synchronization with amp-audio. (#27361)

---
 extensions/amp-story/1.0/page-advancement.js | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/extensions/amp-story/1.0/page-advancement.js b/extensions/amp-story/1.0/page-advancement.js
index 91269ea86c96..8b6c8fba287c 100644
--- a/extensions/amp-story/1.0/page-advancement.js
+++ b/extensions/amp-story/1.0/page-advancement.js
@@ -966,12 +966,17 @@ class MediaBasedAdvancement extends AdvancementConfig {
       this.mediaElement_,
       'Media element was unspecified.'
     );
+
     this.unlistenFns_.push(
       listenOnce(mediaElement, 'ended', () => this.onAdvance())
     );
-    this.unlistenFns_.push(
-      listenOnce(mediaElement, 'timeupdate', () => this.onProgressUpdate())
-    );
+
+    this.onProgressUpdate();
+
+    this.timer_.poll(POLL_INTERVAL_MS, () => {
+      this.onProgressUpdate();
+      return !this.isRunning();
+    });
   }
 
   /** @private */