[selectors4] Implement :focus-within pseudo-class

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

 /*
  * 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 22 matching lines @@
 namespace blink {
 
 class Node;
 class Element;
 
 class UserActionElementSet final {
   DISALLOW_NEW();
 
  public:
   bool IsFocused(const Node* node) { return HasFlags(node, kIsFocusedFlag); }
+  bool HasFocusWithin(const Node* node) {
+    return HasFlags(node, kHasFocusWithinFlag);
+  }
   bool IsActive(const Node* node) { return HasFlags(node, kIsActiveFlag); }
   bool IsInActiveChain(const Node* node) {
     return HasFlags(node, kInActiveChainFlag);
   }
   bool IsDragged(const Node* node) { return HasFlags(node, kIsDraggedFlag); }
   bool IsHovered(const Node* node) { return HasFlags(node, kIsHoveredFlag); }
   void SetFocused(Node* node, bool enable) {
     SetFlags(node, enable, kIsFocusedFlag);
   }
+  void SetHasFocusWithin(Node* node, bool enable) {
+    SetFlags(node, enable, kHasFocusWithinFlag);
+  }
   void SetActive(Node* node, bool enable) {
     SetFlags(node, enable, kIsActiveFlag);
   }
   void SetInActiveChain(Node* node, bool enable) {
     SetFlags(node, enable, kInActiveChainFlag);
   }
   void SetDragged(Node* node, bool enable) {
     SetFlags(node, enable, kIsDraggedFlag);
   }
   void SetHovered(Node* node, bool enable) {
     SetFlags(node, enable, kIsHoveredFlag);
   }
 
   UserActionElementSet();
   ~UserActionElementSet();
 
   void DidDetach(Element&);
 
   DECLARE_TRACE();
 
  private:
   enum ElementFlags {
     kIsActiveFlag = 1,
     kInActiveChainFlag = 1 << 1,
     kIsHoveredFlag = 1 << 2,
     kIsFocusedFlag = 1 << 3,
     kIsDraggedFlag = 1 << 4,
+    kHasFocusWithinFlag = 1 << 5,
   };
 
   void SetFlags(Node* node, bool enable, unsigned flags) {
     enable ? SetFlags(node, flags) : ClearFlags(node, flags);
   }
   void SetFlags(Node*, unsigned);
   void ClearFlags(Node*, unsigned);
   bool HasFlags(const Node*, unsigned flags) const;
 
   void SetFlags(Element*, unsigned);
   void ClearFlags(Element*, unsigned);
   bool HasFlags(const Element*, unsigned flags) const;
 
   typedef HeapHashMap<Member<Element>, unsigned> ElementFlagMap;
   ElementFlagMap elements_;
 };
 
 }  // namespace blink
 
 #endif  // UserActionElementSet_h