Fix caret paint invalidation when moving between blocks

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

Index: third_party/WebKit/Source/core/editing/CaretDisplayItemClient.h
diff --git a/third_party/WebKit/Source/core/editing/CaretDisplayItemClient.h b/third_party/WebKit/Source/core/editing/CaretDisplayItemClient.h
index 2c740f516e5d0ab355188a9d6a217f3575a613fc..576381e0f7a23dae49da8521e18c93c24bd8a043 100644
--- a/third_party/WebKit/Source/core/editing/CaretDisplayItemClient.h
+++ b/third_party/WebKit/Source/core/editing/CaretDisplayItemClient.h
@@ -91,19 +91,33 @@ class CaretDisplayItemClient final : public DisplayItemClient {
   String debugName() const final;
 
  private:
+  void invalidatePaintInCurrentLayoutBlock(
+      const PaintInvalidatorContext&,
+      PaintInvalidationReason layoutBlockPaintInvalidationReason);
+
+  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 m_layoutBlock if m_layoutLayout will change
-  // during updateStyleAndLayoutIfNeeded() and can be used in
-  // invalidatePaintIfNeeded() only.
+  // This is set to the previous value of m_layoutBlock during
+  // updateStyleAndLayoutIfNeeded() and can be used in invalidatePaintIfNeeded()
+  // only.
   const LayoutBlock* m_previousLayoutBlock = nullptr;
 
-  // This is updated by invalidatePaintIfNeeded().
+  // 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;
+
   bool m_needsPaintInvalidation = false;
 };