Fix caret invalidation when a block is removed

third_party/WebKit/Source/core/editing/CaretDisplayItemClient.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
@@ skipping 38 matching lines @@
   // TODO(yosin,wangxianzhu): Make these two static functions private or
   // combine them into updateForPaintInvalidation() when the callsites in
   // FrameCaret are removed.
 
   // Creating VisiblePosition causes synchronous layout so we should use the
   // PositionWithAffinity version if possible.
   // A position in HTMLTextFromControlElement is a typical example.
   static LayoutRect computeCaretRect(const PositionWithAffinity& caretPosition);
   static LayoutBlock* caretLayoutBlock(const Node*);
 
-  // Called indirectly from LayoutObject::clearPreviousVisualRects().
-  void clearPreviousVisualRect(const LayoutBlock& block) {
-    if (shouldPaintCaret(block))
-      m_visualRect = LayoutRect();
-  }
+  // Called indirectly from LayoutBlock::clearPreviousVisualRects().
+  void clearPreviousVisualRect(const LayoutBlock&);
 
-  void layoutBlockWillBeDestroyed(const LayoutBlock& block) {
-    if (!shouldPaintCaret(block))
-      return;
-    m_visualRect = LayoutRect();
-    m_layoutBlock = nullptr;
-  }
+  // Called indirectly from LayoutBlock::willBeDestroyed().
+  void layoutBlockWillBeDestroyed(const LayoutBlock&);
 
   // Called when a FrameView finishes layout. Updates style and geometry of the
   // caret for paint invalidation and painting.
   void updateStyleAndLayoutIfNeeded(const PositionWithAffinity& caretPosition);
 
   // Called during LayoutBlock paint invalidation.
   void invalidatePaintIfNeeded(const LayoutBlock&,
                                const PaintInvalidatorContext&);
 
   bool shouldPaintCaret(const LayoutBlock& block) const {
     return &block == m_layoutBlock;
   }
   void paintCaret(GraphicsContext&,
                   const LayoutPoint& paintOffset,
                   DisplayItem::Type) const;
 
   // DisplayItemClient methods.
   LayoutRect visualRect() const final;
   String debugName() const final;
 
  private:
+  friend class CaretDisplayItemClientTest;
+
   void invalidatePaintInCurrentLayoutBlock(const PaintInvalidatorContext&);
-
   void invalidatePaintInPreviousLayoutBlock(const PaintInvalidatorContext&);
 
   // These are updated by updateStyleAndLayoutIfNeeded().
   Color m_color;
   LayoutRect m_localRect;
   LayoutBlock* m_layoutBlock = nullptr;
 
   // Visual rect of the caret in m_layoutBlock. This is updated by
   // invalidatePaintIfNeeded().
   LayoutRect m_visualRect;
 
   // These are set to the previous value of m_layoutBlock and m_visualRect
   // during updateStyleAndLayoutIfNeeded() if they haven't been set since the
   // last paint invalidation. They can only be used in invalidatePaintIfNeeded()
   // to invalidate the caret in the previous layout block.
   const LayoutBlock* m_previousLayoutBlock = nullptr;
   LayoutRect m_visualRectInPreviousLayoutBlock;
 
   bool m_needsPaintInvalidation = false;
 };
 
 }  // namespace blink
 
 #endif  // CaretDisplayItemClient_h