UserAgent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0

Steps to reproduce the problem:
Install libevent development libraries, build Chromium.

What is the expected behavior?
Chromium is compiled and linked against the system libevent library.

What went wrong?
Chromium unconditionally uses the bundled (out of date) libevent library.

Did this work before? N/A 

Chrome version: 64.0.3282.167  Channel: n/a
OS Version: 
Flash Version: 

This is a clone of https://bugs.chromium.org/p/chromium/issues/detail?id=22140 . A change from 2010 to use the system libevent library was submitted via https://codereview.chromium.org/524061 , but doesn't appear to have made it upstream.