UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36

Steps to reproduce the problem:
We see sporadic issues where Chrome fails to load a PNaCl module. When analyzing the issue in further detail, we found that the DOM <embed> element emits loading events in a weird, repetitive order (ie., "loadstart", followed by a "progress" event with 0 bytes loaded, then back to "loadstart" and so so on).

To reproduce the issue, do the following:

1. Go to clipchamp.com and create an account (it's free)
2. Pick a video file and try to convert it.

We currently re-load the PNaCl module after each step along the way (extracting video metadata, generating a preview image, transcoding the video) such as to have a deterministic, clean state. Sometimes, the throttling behavior is immediately present, ie., we cannot even extract the video metadata. Sometimes it only occurs when generating the preview or transcoding the video and sometimes it even only occurs after transcoding a number of videos.

This is a new issue, which we did not see before Chrome 59. So far, we could reproduce it on a number of platforms: Linux, macOS, and Windows 10.

What is the expected behavior?
The PNaCl module should be successfully loaded, emitting the loading events in the right order (loadstart, progress, loadend). 

What went wrong?
I think this is a regression in Chrome, where the PNaCl subsystem does not get a lot of love ahead of its 2018 retirement. Sad!

Did this work before? Yes Chrome 58, I think

Does this work in other browsers? Yes

Chrome version: 59.0.3071.115  Channel: stable
OS Version: Ubuntu 17.04
Flash Version: