All selectors in :-webkit-any must have an invalidation set feature.

Source/core/css/RuleFeature.cpp

Index: Source/core/css/RuleFeature.cpp
diff --git a/Source/core/css/RuleFeature.cpp b/Source/core/css/RuleFeature.cpp
index 75af986dfdf2af2346bf9c8d28c999733361c3c0..9751e086d94090468bbb04974ec5a1485884f715 100644
--- a/Source/core/css/RuleFeature.cpp
+++ b/Source/core/css/RuleFeature.cpp
@@ -130,13 +130,16 @@ RuleFeatureSet::InvalidationSetMode RuleFeatureSet::invalidationSetModeForSelect
                 foundIdent = true;
         } else if (component->pseudoType() == CSSSelector::PseudoHost || component->pseudoType() == CSSSelector::PseudoAny) {
             if (const CSSSelectorList* selectorList = component->selectorList()) {
+                bool foundUniversal = false;
                 for (const CSSSelector* selector = selectorList->first(); selector; selector = CSSSelectorList::next(*selector)) {
                     InvalidationSetMode hostMode = invalidationSetModeForSelector(*selector);
                     if (hostMode == UseSubtreeStyleChange)
                         return foundCombinator ? UseLocalStyleChange : UseSubtreeStyleChange;
-                    if (!foundCombinator && hostMode == AddFeatures)
-                        foundIdent = true;
+                    if (hostMode == UseLocalStyleChange)

[chrishtr, 2014/07/10 23:26:49]

What does foundUniversal have to do with UseLocalStyleChange? At the very least
this needs
 a big comment.

[rune, 2014/07/11 08:45:14]

Added documentation and renamed hostMode to subSelectorMode.

UseLocalStyleChange means foundIdent was false when returning from
invalidationSetModeForSelector, hence no invalidation set features, and
universal in that sense. Would it be better to call it something like
foundSubSelectorWithoutFeatures instead?

+                        foundUniversal = true;
                 }
+                if (!foundUniversal && !foundCombinator)
+                    foundIdent = true;
             }
         } else if (!isSkippableComponentForInvalidation(*component)) {
             return foundCombinator ? UseLocalStyleChange : UseSubtreeStyleChange;