Change shadow style's scope from Shadow Host to Shadow Root

Source/core/css/SelectorChecker.h

Index: Source/core/css/SelectorChecker.h
diff --git a/Source/core/css/SelectorChecker.h b/Source/core/css/SelectorChecker.h
index 0137d9cc8d9d4f554f63d88032a5b754982169bb..d78a0bbfa8b7aac3dbbc5eb770fe83b861bff982 100644
--- a/Source/core/css/SelectorChecker.h
+++ b/Source/core/css/SelectorChecker.h
@@ -53,10 +53,10 @@ public:
         StaysWithinTreeScope = 2,
         BoundaryBehaviorMask = 3, // 2bit for boundary behavior
         ScopeContainsLastMatchedElement = 4,
-        ScopeIsShadowHost = 8,
+        ScopeIsShadowRoot = 8,
         TreatShadowHostAsNormalScope = 16,
 
-        ScopeIsShadowHostInPseudoHostParameter = ScopeIsShadowHost | TreatShadowHostAsNormalScope
+        ScopeIsShadowHostInPseudoHostParameter = ScopeIsShadowRoot | TreatShadowHostAsNormalScope
     };
 
     struct SelectorCheckingContext {
@@ -179,11 +179,7 @@ inline bool SelectorChecker::checkExactAttribute(const Element& element, const Q
 
 inline bool SelectorChecker::isHostInItsShadowTree(const Element& element, BehaviorAtBoundary behaviorAtBoundary, const ContainerNode* scope)
 {
-    if ((behaviorAtBoundary & (ScopeIsShadowHost | TreatShadowHostAsNormalScope)) == ScopeIsShadowHost)
-        return scope == element;
-    if (scope && scope->isInShadowTree())
-        return scope->shadowHost() == element;
-    return false;
+    return scope && scope->isInShadowTree() && scope->shadowHost() == element;
 }
 
 }