1288030 - Stop BackgroundPageThumbs relying on the hidden window loading chrome: URIs

Status: RESOLVED DUPLICATE of bug 1338215

(Firefox :: New Tab Page, defect)

Description

[:Gijs (he/him)]

Right now the background page thumb code:

1) gets the hidden window;
2) inserts an iframe into it that loads the chrome URI version of about:mozilla
3) inserts a XUL <browser type=content> into that iframe
4) loads pages into there in order to take screenshots and populate the thumbnail db.


When I spoke to Drew on IRC, it seems that when they tried to do this inside a browser window instead, the thumbnails were always completely black, because it wasn't possible to have the browser be display: none or similar and still get it to render.

At the moment this code blocks us from making the hidden window less special (bug 1145470) because it needs to link to this chrome:// URI. Apparently the thumbnailer needs the contents of the iframe to be system-principal'd ( https://dxr.mozilla.org/mozilla-central/rev/4c05938a64a7fde3ac2d7f4493aee1c5f2ad8a0a/toolkit/components/thumbnails/BackgroundPageThumbs.jsm#153-155 ) so I'm not entirely sure how to square that circle. It'd be great if other folks have ideas about how to do that...

Comment 1

[:Gijs (he/him)]

Welp, looks like I fixed this in a dupe.