UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36

Steps to reproduce the problem:
This issue is intermittent and we don't have a repro yet.

For some users, when they have many canvas elements on an inactive browser window, tabbing back to that window will show blank canvas elements instead of the rendered content. 

We encountered a similar issue several months back, and it was fixed: https://codereview.chromium.org/1857763002/

The blank canvas elements started happening intermittently this week, so it may be related to the most recent chrome version.

What is the expected behavior?
Canvas elements show their rendered content when tabbing back to the chrome tab.

What went wrong?
Canvas elements were blank.

Did this work before? Yes Any version before last week

Does this work in other browsers? N/A

Chrome version: 55.0.2883.87  Channel: stable
OS Version: OS X 10.12.1
Flash Version: Shockwave Flash 24.0 r0

Justin Novosad has been helping us investigate and is an awesome human :)