Chromium version: Chromium 62.0.3198.0
Chromium revision: 497674

(1) Run chromium with the following command: 
   ./chrome --headless --screenshot=a.jpg http://www.africau.edu/images/default/sample.pdf

Expected: screenshot saved to a.jpg
Actual: command hangs

Downstream bug: https://github.com/GoogleChrome/puppeteer/issues/610

DevTools protocol reports navigation as canceled. 

(you can debug puppeteer script by using DEBUG=*session node script.js)