[selectors4] Implement :focus-within pseudo-class

third_party/WebKit/Source/core/dom/UserActionElementSet.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 19 matching lines @@
 #include "core/dom/Node.h"
 
 namespace blink {
 
 UserActionElementSet::UserActionElementSet() {}
 
 UserActionElementSet::~UserActionElementSet() {}
 
 void UserActionElementSet::DidDetach(Element& element) {
   DCHECK(element.IsUserActionElement());
-  ClearFlags(&element, kIsActiveFlag | kInActiveChainFlag | kIsHoveredFlag);
+  ClearFlags(&element, kIsActiveFlag | kInActiveChainFlag | kIsHoveredFlag |
+                           kHasFocusWithinFlag);
 }
 
 bool UserActionElementSet::HasFlags(const Node* node, unsigned flags) const {
   DCHECK(node->IsUserActionElement() && node->IsElementNode());
   return HasFlags(ToElement(node), flags);
 }
 
 void UserActionElementSet::SetFlags(Node* node, unsigned flags) {
   if (!node->IsElementNode())
     return;
@@ skipping 48 matching lines @@
 
   element->SetUserActionElement(true);
   elements_.insert(element, flags);
 }
 
 DEFINE_TRACE(UserActionElementSet) {
   visitor->Trace(elements_);
 }
 
 }  // namespace blink