Add support for new CSS ::slotted() pseudo element

third_party/WebKit/Source/core/css/RuleSet.cpp

Index: third_party/WebKit/Source/core/css/RuleSet.cpp
diff --git a/third_party/WebKit/Source/core/css/RuleSet.cpp b/third_party/WebKit/Source/core/css/RuleSet.cpp
index 7839eba7360970244f995cb81d97c6ae6ca9ffe5..ea98fd774fb8b64ee77b394b2838ba25c4f155f2 100644
--- a/third_party/WebKit/Source/core/css/RuleSet.cpp
+++ b/third_party/WebKit/Source/core/css/RuleSet.cpp
@@ -262,6 +262,8 @@ void RuleSet::addChildRules(const WillBeHeapVector<RefPtrWillBeMember<StyleRuleB
                     m_deepCombinatorOrShadowPseudoRules.append(MinimalRuleData(styleRule, selectorIndex, addRuleFlags));
                 } else if (selectorList.selectorHasShadowDistributed(selectorIndex)) {
                     m_shadowDistributedRules.append(MinimalRuleData(styleRule, selectorIndex, addRuleFlags));
+                } else if (selectorList.selectorHasShadowSlotted(selectorIndex)) {
+                    m_shadowSlottedRules.append(MinimalRuleData(styleRule, selectorIndex, addRuleFlags));
                 } else {
                     addRule(styleRule, selectorIndex, addRuleFlags);
                 }
@@ -342,6 +344,7 @@ void RuleSet::compactRules()
     m_keyframesRules.shrinkToFit();
     m_deepCombinatorOrShadowPseudoRules.shrinkToFit();
     m_shadowDistributedRules.shrinkToFit();
+    m_shadowSlottedRules.shrinkToFit();
 }
 
 DEFINE_TRACE(MinimalRuleData)
@@ -383,6 +386,7 @@ DEFINE_TRACE(RuleSet)
     visitor->trace(m_keyframesRules);
     visitor->trace(m_deepCombinatorOrShadowPseudoRules);
     visitor->trace(m_shadowDistributedRules);
+    visitor->trace(m_shadowSlottedRules);
     visitor->trace(m_viewportDependentMediaQueryResults);
     visitor->trace(m_pendingRules);
 #ifndef NDEBUG