Implement matching part of ::slotted() pseudo element

third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp

Index: third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp
diff --git a/third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp b/third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp
index 8cebdbfe462806bccfea4add451ebe48ec1292ff..1a2a83d382be54bee6fb46b8942ea4611664cb15 100644
--- a/third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp
@@ -207,7 +207,8 @@ static void addRules(RuleSet* ruleSet, const WillBeHeapVector<MinimalRuleData>&
 void ScopedStyleResolver::addTreeBoundaryCrossingRules(const RuleSet& authorRules, CSSStyleSheet* parentStyleSheet, unsigned sheetIndex)
 {
     bool isDocumentScope = treeScope().rootNode().isDocumentNode();
-    if (authorRules.deepCombinatorOrShadowPseudoRules().isEmpty() && (isDocumentScope || authorRules.shadowDistributedRules().isEmpty()))
+    if (authorRules.deepCombinatorOrShadowPseudoRules().isEmpty()
+        && (isDocumentScope || (authorRules.shadowDistributedRules().isEmpty() && authorRules.shadowSlottedRules().isEmpty())))
         return;
 
     if (!authorRules.deepCombinatorOrShadowPseudoRules().isEmpty())
@@ -216,8 +217,10 @@ void ScopedStyleResolver::addTreeBoundaryCrossingRules(const RuleSet& authorRule
     OwnPtrWillBeRawPtr<RuleSet> ruleSetForScope = RuleSet::create();
     addRules(ruleSetForScope.get(), authorRules.deepCombinatorOrShadowPseudoRules());
 
-    if (!isDocumentScope)
+    if (!isDocumentScope) {
         addRules(ruleSetForScope.get(), authorRules.shadowDistributedRules());

[rune, 2016/01/20 12:53:32]

Should this now be named shadowContentRules, since ::slotted is also a rule for
distributed elements? IIRC, you renamed from Distributed to Content in the
parser CL.

[kochi, 2016/01/21 05:09:37]

Yes, we also have SelectorChecker::matchForShadowDistributed(), so I'd like to
rename
all of occurrences in another CL.

[rune, 2016/01/21 07:18:04]

Acknowledged.

+        addRules(ruleSetForScope.get(), authorRules.shadowSlottedRules());
+    }
 
     if (!m_treeBoundaryCrossingRuleSet) {
         m_treeBoundaryCrossingRuleSet = adoptPtrWillBeNoop(new CSSStyleSheetRuleSubSet());