Add CaretBase::m_caretPainter, and compute caretBrowsing lazily.

Source/core/editing/Caret.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 41 matching lines @@
     // PositionWithAffinity version if possible.
     // A position in HTMLTextFromControlElement is a typical example.
     bool updateCaretRect(Document*, const PositionWithAffinity& caretPosition);
     bool updateCaretRect(Document*, const VisiblePosition& caretPosition);
     IntRect absoluteBoundsForLocalRect(Node*, const LayoutRect&) const;
     bool shouldRepaintCaret(Node&) const;
     bool shouldRepaintCaret(const LayoutView*) const;
     void paintCaret(Node*, GraphicsContext*, const LayoutPoint&, const LayoutRect& clipRect) const;
 
     const LayoutRect& localCaretRectWithoutUpdate() const { return m_caretLocalRect; }
+    LayoutBlock* caretPainter() const { return m_caretPainter; }
 
     void setCaretVisibility(CaretVisibility visibility) { m_caretVisibility = visibility; }
     bool caretIsVisible() const { return m_caretVisibility == Visible; }
     CaretVisibility caretVisibility() const { return m_caretVisibility; }
 
-protected:
     static LayoutBlock* caretLayoutObject(Node*);
     static void invalidateLocalCaretRect(Node*, const LayoutRect&);
 
 private:
+    LayoutBlock* m_caretPainter; // layout object responsible for painting the caret
     LayoutRect m_caretLocalRect; // caret rect in coords local to the layoutObject responsible for painting the caret
     CaretVisibility m_caretVisibility;
 };
 
 class DragCaretController final : public NoBaseWillBeGarbageCollected<DragCaretController>, private CaretBase {
     WTF_MAKE_NONCOPYABLE(DragCaretController);
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(DragCaretController);
 public:
     static PassOwnPtrWillBeRawPtr<DragCaretController> create();
 
-    LayoutBlock* caretLayoutObject() const;
+    LayoutBlock* caretLayoutObject() const { return CaretBase::caretPainter(); }
     void paintDragCaret(LocalFrame*, GraphicsContext*, const LayoutPoint&, const LayoutRect& clipRect) const;
 
     bool isContentEditable() const { return m_position.rootEditableElement(); }
     bool isContentRichlyEditable() const;
 
     bool hasCaret() const { return m_position.isNotNull(); }
     const VisiblePosition& caretPosition() { return m_position; }
     void setCaretPosition(const VisiblePosition&);
     void clear() { setCaretPosition(VisiblePosition()); }
 
     void nodeWillBeRemoved(Node&);
 
     DECLARE_TRACE();
 
 private:
     DragCaretController();
 
     VisiblePosition m_position;
 };
 
 } // namespace blink
 
 
 #endif // Caret_h