Currently we always show the fullscreen approval UI/enter warning whenever we enter fullscreen or rollback fullscreen to the previous element. I think this behaviour is annoying; if you've approved a domain for fullscreen, then requesting fullscreen in another element on the same domain (say in a video on that page) will cause another "$domain is now fullscreen" warning. I don't think it makes sense to warn again in the same-origin case, since the current domain is trusted. I think we should only show the warning/approval UI when: * We request/rollback fullscreen in/to a document cross-origin, or * When requesting fullscreen in a document that hasn't already been approved for fullscreen by the permission manager or by an explicit grant by the user. The cross-origin case should always trump; we should still show the warning when entering a fullscreen on a pre-approved origin cross domain. So this patch changes behaviour so that we only show the fullscreen warning/approval UI when fullscreen is requested in different origin than the previous fullscreen element, or when a document isn't already approved by permission or explicit approval.
Created attachment 625585 [details] [diff] [review] Patch: MozEnteredDomFullscreen dispatch change We dispatch MozEnteredDomFullscreen in order to signal to chrome when it should display the warning/approval UI, so alter its firing to only fire on unapproved or cross-origin domains. Greenish on Try: https://tbpl.mozilla.org/?tree=Try&rev=51fda017a10d (Builds there if you want to test behaviour too)