UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

Steps to reproduce the problem:
1. Ubuntu 18.04 system with an NVIDIA 980 or 1070 card (these are the only 2 cards I have) using Chrome or Chromium with the NVIDIA proprietary drivers.
2. Open Chrome/Chromium to https://www.khronos.org/registry/webgl/sdk/tests/webgl-conformance-tests.html and run the all/conformance/reading tests.
3. The 2nd and 3rd of the 3 read pixels tests will fail.

What is the expected behavior?
The read pixel conformance tests should pass.

These tests do pass on Firefox, and web pages that use read pixels (photoeditor.polarr.co) function correctly in Firefox on Ubuntu 18.04 but not in Chrome.

What went wrong?
Read pixel values are all 0,0,0 in Chrome and Chromium.

Did this work before? N/A 

Does this work in other browsers? N/A

Chrome version: 65.0.3325.181  Channel: stable
OS Version: Ubuntu 18.04
Flash Version: 

I originally reported this bug on LaunchPad and was directed to open an issue here. Apport collected my system information and attached it to the issue on Launchpad.
https://bugs.launchpad.net/ubuntu/+source/chromium-browser/+bug/1764648

Ubuntu 18.04 is in final beta and is scheduled for release on April 26th.