Fix caret paint invalidation issues

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 86 matching lines @@
 
   void invalidatePaintInPreviousLayoutBlock(
       const PaintInvalidatorContext&,
       PaintInvalidationReason layoutBlockPaintInvalidationReason);
 
   // These are updated by updateStyleAndLayoutIfNeeded().
   Color m_color;
   LayoutRect m_localRect;
   LayoutBlock* m_layoutBlock = nullptr;
 
-  // This is set to the previous value of m_layoutBlock during
-  // updateStyleAndLayoutIfNeeded() and can be used in invalidatePaintIfNeeded()
-  // only.
-  const LayoutBlock* m_previousLayoutBlock = nullptr;
-
   // Visual rect of the caret in m_layoutBlock. This is updated by
   // invalidatePaintIfNeeded().
   LayoutRect m_visualRect;
 
-  // This is set to the previous value of m_visualRect during
-  // updateStyleAndLayoutIfNeeded() and can be used in invalidatePaintIfNeeded()
-  // only.
-  LayoutRect m_previousVisualRect;
+  // 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