http://code.google.com/p/chromium/issues/detail?id=102521 What steps will reproduce the problem? 1. Maps.google.com 2. Look for directions 3. By Car and By Transport What is the expected result? Lines depicting the path to take What happens instead? Lines are not visible Icons are misaligned Bisection identified http://trac.webkit.org/changeset/98542 as the change that caused the regression.
A minimal temporary fix is to simply disable the MatchedDeclarationCache by adding "result.isCacheable = false;" to the end of CSSStyleSelector::matchAllRules().
Created attachment 114434 [details] Patch
I haven't been able to repro the missing direction lines, but I the misaligned icons does occur in WebKit Nightly r99757. Antti - this looks like it might be a dupe of https://bugs.webkit.org/show_bug.cgi?id=71703, since they both seem to have been caused by the same patch as identified by David?
Comment on attachment 114434 [details] Patch Disabling the feature stops us from getting testing. I don't think we should do this as the bug does not make the build unlivable.
Could some from Google provide a reduced test case for this? maps.google.com is generally difficult to debug due to obfuscation.
The feature has already been demonstrated to cause at least two regressions, this one on a live site and https://bugs.webkit.org/show_bug.cgi?id=71703. While we don't have a minimal repro yet, the feature really doesn't seem to be working as intended ie no side effects other than memory/performance improvements. Wouldn't it be better to roll this back, or effectively disable it as in David's patch so it can be examined offline? Also, the feature was submitted with no new tests - are you confident that all the new code was covered by the existing tests?
Created attachment 114625 [details] Small but not minimal repro of maps alignment issue This is still quite messy but is sufficient to demonstrate a change in behavior.
Created attachment 114627 [details] Slightly better repro, visible difference when served by http
Created attachment 114655 [details] Minimal reproduction Should see concentric squares but the middle square moves to the top.
Great, thank! I'm on it.
Thank you very much for the reduction, david.
Created attachment 114830 [details] fix Turns out that r98542 exposed that there is a field missing from StyleBoxData copy constructor.
http://trac.webkit.org/changeset/100078
ouch! Thanks antti!
Thanks for the quick fix Antti!
Thank you, Antti! I've tested rolling the change into Chrome and it's all good news.