Fix caret invalidation when a block is removed

third_party/WebKit/Source/core/editing/CaretDisplayItemClient.cpp

 /*
  * Copyright (C) 2004, 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 97 matching lines @@
   // Get the layoutObject that will be responsible for painting the caret
   // (which is either the layoutObject we just found, or one of its containers).
   LayoutBlockItem caretPainterItem =
       LayoutBlockItem(caretLayoutBlock(caretPosition.anchorNode()));
   LayoutRect caretLocalRectWithWritingMode = caretLocalRect;
   caretPainterItem.flipForWritingMode(caretLocalRectWithWritingMode);
   return mapCaretRectToCaretPainter(LayoutItem(layoutObject), caretPainterItem,
                                     caretLocalRectWithWritingMode);
 }
 
+void CaretDisplayItemClient::clearPreviousVisualRect(const LayoutBlock& block) {
+  if (block == m_layoutBlock) {
+    m_visualRect = LayoutRect();
+    m_localRect = LayoutRect();
+  }
+  if (block == m_previousLayoutBlock)
+    m_visualRectInPreviousLayoutBlock = LayoutRect();
+}
+
+void CaretDisplayItemClient::layoutBlockWillBeDestroyed(
+    const LayoutBlock& block) {
+  if (block == m_layoutBlock)
+    m_layoutBlock = nullptr;
+  if (block == m_previousLayoutBlock)
+    m_previousLayoutBlock = nullptr;
+}
+
 void CaretDisplayItemClient::updateStyleAndLayoutIfNeeded(
     const PositionWithAffinity& caretPosition) {
   // This method may be called multiple times (e.g. in partial lifecycle
   // updates) before a paint invalidation. We should save m_previousLayoutBlock
   // and m_visualRectInPreviousLayoutBlock only if they have not been saved
   // since the last paint invalidation to ensure the caret painted in the
   // previous paint invalidated block will be invalidated. We don't care about
   // intermediate changes of layoutBlock because they are not painted.
   if (!m_previousLayoutBlock) {
     m_previousLayoutBlock = m_layoutBlock;
@@ skipping 143 matching lines @@
 
 String CaretDisplayItemClient::debugName() const {
   return "Caret";
 }
 
 LayoutRect CaretDisplayItemClient::visualRect() const {
   return m_visualRect;
 }
 
 }  // namespace blink