[css-display] Support display: contents pseudo-elements.

third_party/WebKit/Source/core/dom/PseudoElement.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 21 matching lines @@
 #include "core/style/ComputedStyle.h"
 
 namespace blink {
 
 class CORE_EXPORT PseudoElement : public Element {
  public:
   static PseudoElement* create(Element* parent, PseudoId);
 
   PassRefPtr<ComputedStyle> customStyleForLayoutObject() override;
   void attachLayoutTree(const AttachContext& = AttachContext()) override;
+  void detachLayoutTree(const AttachContext& = AttachContext()) override;
   bool layoutObjectIsNeeded(const ComputedStyle&) override;
 
   bool canStartSelection() const override { return false; }
   bool canContainRangeEndPoint() const override { return false; }
   PseudoId getPseudoId() const override { return m_pseudoId; }
 
   static String pseudoElementNameForEvents(PseudoId);
 
   Node* findAssociatedNode() const;
 
   virtual void dispose();
 
  protected:
   PseudoElement(Element*, PseudoId);
 
  private:
   void didRecalcStyle() override;
 
   PseudoId m_pseudoId;
+  std::vector<LayoutObject*> m_generatedContent;

[emilio, 2017/03/13 13:28:31]

This can also go away now.

 };
 
 const QualifiedName& pseudoElementTagName();
 
 inline bool pseudoElementLayoutObjectIsNeeded(const ComputedStyle* style) {
   if (!style)
     return false;
   if (style->display() == EDisplay::None)
     return false;
   if (style->styleType() == PseudoIdFirstLetter ||
       style->styleType() == PseudoIdBackdrop)
     return true;
   return style->contentData();
 }
 
 DEFINE_ELEMENT_TYPE_CASTS(PseudoElement, isPseudoElement());
 
 }  // namespace blink
 
 #endif