UserAgent: Mozilla/5.0 (Windows NT 6.3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36

Steps to reproduce the problem:
1. Open https://www.youtube.com/upload
2. Upload a long video
3. Switch to another tabs

What is the expected behavior?
The video upload should be completed in the background tab.

What went wrong?
The YouTube Upload tab got discarded / suspended while uploading and I need to upload the video again. It causes a waste of time and outbound traffic.

Did this work before? N/A 

Chrome version: 51.0.2704.103  Channel: n/a
OS Version: 6.3
Flash Version: Shockwave Flash 22.0 r0

It probably affects Vimeo too.