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

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

Index: third_party/WebKit/Source/core/css/SelectorFilter.cpp
diff --git a/third_party/WebKit/Source/core/css/SelectorFilter.cpp b/third_party/WebKit/Source/core/css/SelectorFilter.cpp
index 140ebaf4873e55337e0a2c3c21baec57995eb83c..2fe5abdbc98f69c1b77c8b42f65ada541558ad3c 100644
--- a/third_party/WebKit/Source/core/css/SelectorFilter.cpp
+++ b/third_party/WebKit/Source/core/css/SelectorFilter.cpp
@@ -134,7 +134,7 @@ void SelectorFilter::collectIdentifierHashes(const CSSSelector& selector, unsign
     unsigned* hash = identifierHashes;
     unsigned* end = identifierHashes + maximumIdentifierCount;
     CSSSelector::Relation relation = selector.relation();
-    bool relationIsAffectedByPseudoContent = selector.relationIsAffectedByPseudoContent();
+    bool relationIsAffectedByPseudoContentOrSlotted = selector.relationIsAffectedByPseudoContent() || selector.relationIsAffectedByPseudoSlotted();
 
     // Skip the topmost selector. It is handled quickly by the rule hashes.
     bool skipOverSubselectors = true;
@@ -151,7 +151,8 @@ void SelectorFilter::collectIdentifierHashes(const CSSSelector& selector, unsign
             break;
         case CSSSelector::Descendant:
         case CSSSelector::Child:
-            if (relationIsAffectedByPseudoContent) {
+        case CSSSelector::ShadowSlot:
+            if (relationIsAffectedByPseudoContentOrSlotted) {
                 // Disable fastRejectSelector.
                 *identifierHashes = 0;
                 return;
@@ -166,7 +167,7 @@ void SelectorFilter::collectIdentifierHashes(const CSSSelector& selector, unsign
         if (hash == end)
             return;
         relation = current->relation();
-        relationIsAffectedByPseudoContent = current->relationIsAffectedByPseudoContent();
+        relationIsAffectedByPseudoContentOrSlotted = current->relationIsAffectedByPseudoContent() || current->relationIsAffectedByPseudoSlotted();
     }
     *hash = 0;
 }