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

third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp

Index: third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp
diff --git a/third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp b/third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp
index 564b31d911422b116489cadc7ae64a29019c36c6..29d0b14ac16c16ded20b20671f15a0a94582320d 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp
+++ b/third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp
@@ -24,6 +24,9 @@ static void recordSelectorStats(const CSSParserContext& context, const CSSSelect
             case CSSSelector::PseudoUnresolved:
                 feature = UseCounter::CSSSelectorPseudoUnresolved;
                 break;
+            case CSSSelector::PseudoSlotted:
+                feature = UseCounter::CSSSelectorPseudoSlotted;
+                break;
             case CSSSelector::PseudoContent:
                 feature = UseCounter::CSSSelectorPseudoContent;
                 break;
@@ -360,6 +363,7 @@ PassOwnPtr<CSSParserSelector> CSSSelectorParser::consumePseudo(CSSParserTokenRan
             selector->setSelectorList(selectorList.release());
             return selector.release();
         }
+    case CSSSelector::PseudoSlotted:
     case CSSSelector::PseudoNot:
         {
             OwnPtr<CSSParserSelector> innerSelector = consumeCompoundSelector(block);
@@ -369,6 +373,8 @@ PassOwnPtr<CSSParserSelector> CSSSelectorParser::consumePseudo(CSSParserTokenRan
             Vector<OwnPtr<CSSParserSelector>> selectorVector;
             selectorVector.append(innerSelector.release());
             selector->adoptSelectorVector(selectorVector);
+            if (selector->pseudoType() == CSSSelector::PseudoSlotted)
+                selector->setRelationIsAffectedByPseudoSlotted();
             return selector.release();
         }
     case CSSSelector::PseudoLang:
@@ -576,8 +582,8 @@ void CSSSelectorParser::prependTypeSelectorIfNeeded(const AtomicString& namespac
     if (compoundSelector->crossesTreeScopes())
         return rewriteSpecifiersWithElementNameForCustomPseudoElement(tag, compoundSelector, elementName.isNull());
 
-    if (compoundSelector->pseudoType() == CSSSelector::PseudoContent)
-        return rewriteSpecifiersWithElementNameForContentPseudoElement(tag, compoundSelector, elementName.isNull());
+    if (compoundSelector->pseudoType() == CSSSelector::PseudoContent || compoundSelector->pseudoType() == CSSSelector::PseudoSlotted)
+        return rewriteSpecifiersWithElementNameForContentOrSlottedPseudoElement(tag, compoundSelector, elementName.isNull());
 
     // *:host never matches, so we can't discard the * otherwise we can't tell the
     // difference between *:host and just :host.
@@ -609,13 +615,14 @@ void CSSSelectorParser::rewriteSpecifiersWithElementNameForCustomPseudoElement(c
     lastShadowPseudo->setRelation(CSSSelector::ShadowPseudo);
 }
 
-void CSSSelectorParser::rewriteSpecifiersWithElementNameForContentPseudoElement(const QualifiedName& tag, CSSParserSelector* specifiers, bool tagIsImplicit)
+void CSSSelectorParser::rewriteSpecifiersWithElementNameForContentOrSlottedPseudoElement(const QualifiedName& tag, CSSParserSelector* specifiers, bool tagIsImplicit)
 {
     CSSParserSelector* last = specifiers;
     CSSParserSelector* history = specifiers;
     while (history->tagHistory()) {
         history = history->tagHistory();
-        if (history->pseudoType() == CSSSelector::PseudoContent || history->relationIsAffectedByPseudoContent())
+        if (history->pseudoType() == CSSSelector::PseudoContent || history->relationIsAffectedByPseudoContent()
+            || history->pseudoType() == CSSSelector::PseudoSlotted || history->relationIsAffectedByPseudoSlotted())
             last = history;
     }
 
@@ -625,10 +632,10 @@ void CSSSelectorParser::rewriteSpecifiersWithElementNameForContentPseudoElement(
         return;
     }
 
-    // For shadow-ID pseudo-elements to be correctly matched, the ShadowPseudo combinator has to be used.
-    // We therefore create a new Selector with that combinator here in any case, even if matching any (host) element in any namespace (i.e. '*').
     OwnPtr<CSSParserSelector> elementNameSelector = CSSParserSelector::create(tag);
     last->setTagHistory(elementNameSelector.release());
+    if (last->pseudoType() == CSSSelector::PseudoSlotted)
+        last->setRelation(CSSSelector::ShadowSlot);
 }
 
 PassOwnPtr<CSSParserSelector> CSSSelectorParser::addSimpleSelectorToCompound(PassOwnPtr<CSSParserSelector> compoundSelector, PassOwnPtr<CSSParserSelector> simpleSelector)