b88a6a63f5
This was a memory-saving optimization introduced as part of dependencies for bug 686875, but a more general system landed in bug 77999 for Gecko and https://github.com/servo/servo/pull/18509 for Servo. So now it's probably even a bit of a pessimization (though probably not huge), and given this causes bugs like bug 1462742, bug 1157592, and bug 1468145, and fishiness like the one pointed out in this bug, we may as well remove it. The performance impact of having to lookup through more rules should be minimal given the bloom filter and the rule hash optimizations. This makes me wonder whether we could remove the whole concept of on-demand UA sheets, since they've caused pain, for example, when the frontend people try loading <svg>s from NAC (since that triggers sheet loading from frame construction, which is not good). I'm not concerned about loading mathml.css and svg.css everywhere, though xul.css may not be as doable since it adds a bunch of attribute-dependent selectors. Though on the other hand I asserted in the xul.css code and we don't load it in content with <video> / <input type="date/time/etc"> and such, afaict, so maybe now that legacy addons are gone we can remove that sheet from content processes altogether. MozReview-Commit-ID: 9JCWNZj6BkT
An explanation of the Mozilla Source Code Directory Structure and links to
project pages with documentation can be found at:
https://developer.mozilla.org/en/Mozilla_Source_Code_Directory_Structure
For information on how to build Mozilla from the source code, see:
https://developer.mozilla.org/en/docs/Build_Documentation
To have your bug fix / feature added to Mozilla, you should create a patch and
submit it to Bugzilla (https://bugzilla.mozilla.org). Instructions are at:
https://developer.mozilla.org/en/docs/Creating_a_patch
https://developer.mozilla.org/en/docs/Getting_your_patch_in_the_tree
If you have a question about developing Mozilla, and can't find the solution
on https://developer.mozilla.org, you can try asking your question in a
mozilla.* Usenet group, or on IRC at irc.mozilla.org. [The Mozilla news groups
are accessible on Google Groups, or news.mozilla.org with a NNTP reader.]
You can download nightly development builds from the Mozilla FTP server.
Keep in mind that nightly builds, which are used by Mozilla developers for
testing, may be buggy. Firefox nightlies, for example, can be found at:
https://archive.mozilla.org/pub/firefox/nightly/latest-mozilla-central/
- or -
https://www.mozilla.org/firefox/channel/desktop/#nightly