Created attachment 8921538 [details] html page containing a video User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:55.0) Gecko/20100101 Firefox/55.0 Build ID: 20170826053331 Steps to reproduce: Attempted to block a video using chrome.webRequest.onBeforeRequest(...) Actual results: The video was not blocked when video.play() was used. Expected results: The video should have been blocked.
I can't reproduce this on OS X in Firefox release (56) up to Nightly (58). Your user agent in the bug mentions 55. Can you reproduce in any of these versions?
Yes, this reproduces with nightly (58) on Android. It does not reproduce on the desktop version.