Make a '::distributed' pseudo element the first-ever client who can accept a relative selector.

Source/core/css/CSSParser.cpp

Index: Source/core/css/CSSParser.cpp
diff --git a/Source/core/css/CSSParser.cpp b/Source/core/css/CSSParser.cpp
index afd38282f1f58ee546f393c5cad2003f61e77870..fc6b772ebc7bbd20dd0126fa25b16b7f6d074584 100644
--- a/Source/core/css/CSSParser.cpp
+++ b/Source/core/css/CSSParser.cpp
@@ -11127,9 +11127,19 @@ CSSParserSelector* CSSParser::rewriteSpecifiersForShadowDistributed(CSSParserSel
     CSSParserSelector* end = argumentSelector;
     while (end->tagHistory())
         end = end->tagHistory();
-    end->setTagHistory(sinkFloatingSelector(specifiers));
-    end->setRelation(CSSSelector::ShadowDistributed);
-    return argumentSelector;
+
+    switch (end->relation()) {
+    case CSSSelector::Child:
+        end->setTagHistory(sinkFloatingSelector(specifiers));
+        end->setRelation(CSSSelector::ShadowVirtualChild);

[dglazkov, 2013/05/22 17:43:43]

This is where it's fairly clear that we're just overloading Relation.

+        return argumentSelector;
+    case CSSSelector::Descendant:
+        end->setTagHistory(sinkFloatingSelector(specifiers));
+        end->setRelation(CSSSelector::ShadowVirtualDescendant);
+        return argumentSelector;
+    default:
+        return 0;
+    }
 }
 
 CSSParserSelector* CSSParser::rewriteSpecifiers(CSSParserSelector* specifiers, CSSParserSelector* newSpecifier)