mozilla/pdf.js — pull request #5090 by Rob--W (2014-07-25 20:48:22+00:00)
Title: Re-run feature detection after downgrading the Chromium browser.

If a user downgrades from Chromium 35+ to 34, then the PDF Viewer extension will not work any more because the extension assumes that certain features were available based on the cached feature detection results.

To resolve this problem, all feature detection tests run again if the browser was downgraded.