In computed style, for an invalid URL, nsROCSSPrimitiveValue.cpp sometimes generates url(invalid-url:), because we had to generate something for invalid URLs. http://dev.w3.org/csswg/css3-values/ describes url(about:invalid) for a similar purpose, so we should switch this to being about:invalid instead.
Created attachment 659681 [details] [diff] [review] Trivial patch switching from url(invalid-url:) to url(about:invalid)
Comment on attachment 659681 [details] [diff] [review] Trivial patch switching from url(invalid-url:) to url(about:invalid) Perhaps add a comment saying something like: // http://dev.w3.org/csswg/css3-values/#attr-notation defines // about:invalid for a similar purpose, so let's also use it // here as the computed value for invalid URLs. Though I wonder if it's an issue that this *does* round trip to something meaningful. (Might we need to make about:invalid produce a particular empty document?)
Spec says: The about:invalid URI references a non-existent document with a generic error condition. It can be used when a URI is necessary, but the default value shouldn't be resolveable as any type of document. So I think the answer to the last part of comment 2 is "no".
Created attachment 660097 [details] [diff] [review] new patch, updated after review
Comment on attachment 660097 [details] [diff] [review] new patch, updated after review When I asked if it was an issue, I was more worried about "for the Web" than "according to the spec". But I suppose let's go ahead and do this, even though it's a little weird.
setting the checkin-needed keyword as I don't have the level 2 commit bit yet
I don't see a Try link here, so I've pushed it myself. I'll land this if it's green. https://tbpl.mozilla.org/?tree=Try&rev=e29c3fd60ea9
https://hg.mozilla.org/integration/mozilla-inbound/rev/c01e44583414 Should this have a test?