The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5c777ff51727a999e4a5b5f0dbc95faa7e19e53c

commit 5c777ff51727a999e4a5b5f0dbc95faa7e19e53c
Author: Fernando Serboncini <fserb@chromium.org>
Date: Tue May 29 21:03:31 2018

Fix test timeout on Canvas tests

This fixes the test, but not the underlying problem. A separate bug
has been created to track this

TBR=junov

Bug:  810437 ,847594
Change-Id: Id142b936af3378385b4fcc199ed193f5a0fb2241
Reviewed-on: https://chromium-review.googlesource.com/1077098
Reviewed-by: Fernando Serboncini <fserb@chromium.org>
Commit-Queue: Fernando Serboncini <fserb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562583}
[modify] https://crrev.com/5c777ff51727a999e4a5b5f0dbc95faa7e19e53c/third_party/WebKit/LayoutTests/SlowTests
[modify] https://crrev.com/5c777ff51727a999e4a5b5f0dbc95faa7e19e53c/third_party/WebKit/LayoutTests/fast/canvas/canvas-filter-removed-expected.html
[modify] https://crrev.com/5c777ff51727a999e4a5b5f0dbc95faa7e19e53c/third_party/WebKit/LayoutTests/fast/canvas/canvas-filter-removed.html

Have you traced the code? What is the long pole code component?

Also, what's an example test?

I didn't trace it, because I can't repro on chrome, only on the tests. (Can one trace layout tests?)

It seems to be related to the swiftshader change, I'll try to repro switching it off today.