Build Identifier: http://hg.mozilla.org/mozilla-central/rev/bfd85c9652fa Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20121219 Firefox/20.0 ID:20121219030847 deleting startupCache fixes the problem. Steps to reproduce: 1. Create new profile and Start Browser with the profile 2. Set media.windows-media-foundation.enabled to true in about:config 3. Restart Browser 4. Open Error Console (Ctrl+Shift+J) 5. Open http://www.quirksmode.org/html5/tests/video.html and Wait for page loading completion 6. Repeat step 3-5 four times Actual results: All HTML5 videos can not play back. Error: Error: Permission denied to access property 'getAttribute' Source file: chrome://global/content/bindings/scale.xml Line: 90 ---------- Error: Error: Permission denied to access property 'Utils' Source file: chrome://global/content/bindings/videocontrols.xml Line: 116 ---------- Error: Error: Permission denied to access property 'getAttribute' Source file: chrome://global/content/bindings/scale.xml Line: 90 ---------- Error: Error: Permission denied to access property 'Utils' Source file: chrome://global/content/bindings/videocontrols.xml Line: 116 ---------- Error: Error: Permission denied to access property '_setIntegerAttribute' Source file: chrome://global/content/bindings/scale.xml Line: 53 Expected results: All HTML5 videos should be able to play back. There should not be any error.

Regression window(m-c) Good: http://hg.mozilla.org/mozilla-central/rev/edd45de440ba Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20121213 Firefox/20.0 ID:20121213030751 Bad: http://hg.mozilla.org/mozilla-central/rev/9db79b97abbb Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20121213 Firefox/20.0 ID:20121213075622 Pushlog; http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=edd45de440ba&tochange=9db79b97abbb Regression window(m-i) Good: http://hg.mozilla.org/integration/mozilla-inbound/rev/c4b354cd4b98 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20121212 Firefox/20.0 ID:20121212170621 Bad: http://hg.mozilla.org/integration/mozilla-inbound/rev/1001e245b6ba Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20121212 Firefox/20.0 ID:20121212171021 Pushlog; http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=c4b354cd4b98&tochange=1001e245b6ba Suspected: Bug 818716

Looks like XBL code read in from the XUL prototype cache doesn't properly get marked as XBL. Patch coming up.

Thanks Alice :-)

Comment on attachment 694155 [details] [diff] [review] Mark deserialized XBL script as XBL. v1 r=me

User Agent: Mozilla/5.0 (Windows NT 6.1; rv:20.0) Gecko/20100101 Firefox/20.0 Reproduced this issue with Nightly from 2012-12-19 (Build ID: 20121219030847), I have encountered the same errors in console as in comment 0. Verified as fixed on Firefox 20 beta 7 (Build ID: 20130325214615) - no errors in console.