897820 - Use private-browsing background thumbnailing service for cache-control: no-cache

Status: NEW

(Firefox :: General, defect)

Description

[Jared Wein [:jaws] (please needinfo? me)]

From this Reddit post (NSFW), http://www.reddit.com/r/funny/comments/1iyj83/damnit_google_chrome/, a user complained that Chrome had captured a thumbnail of their reddit page showing nudity and placed that thumbnail on their New Tab Page.

reddit.com sends a cache-control: no-cache header, and now that we have a way to retrieve thumbnails of cache-control: no-store sites, I think we should expand that to include cache-control: no-cache sites.

From my simple reading of the code, it looks like to do this we would only need to add another condition at http://hg.mozilla.org/mozilla-central/annotate/a4c1961bf723/browser/base/content/browser-thumbnails.js#l180 to include a check for httpChannel.isNoCacheResponse().

Comment 1

[Mark Hammond [:markh] [:mhammond]]

To clarify here, what seems to have happened is that a combination of some addon and user interaction caused the page to become NSFW when it otherwise would have been.  So if the b/g service was used to capture this page, it probably would have been fine.

If the page had NSFW content without any user interaction, then the proposed fix here would have had no impact - the "foreground" service would decline to capture it, but the background service would then dutifuly grab it - but that isn't what this bug is trying to fix.