Invalidate the previous caret location when editing text nodes.

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

Index: third_party/WebKit/Source/core/editing/FrameSelection.cpp
diff --git a/third_party/WebKit/Source/core/editing/FrameSelection.cpp b/third_party/WebKit/Source/core/editing/FrameSelection.cpp
index e26488ebe4424e0bab75c793ed08199a137e74b2..ea08e76c8afb43e642169a58f03989b5998b06b0 100644
--- a/third_party/WebKit/Source/core/editing/FrameSelection.cpp
+++ b/third_party/WebKit/Source/core/editing/FrameSelection.cpp
@@ -733,6 +733,15 @@ void FrameSelection::invalidateCaretRect()
     m_previousCaretVisibility = m_caretBase->getCaretVisibility();
 }
 
+void FrameSelection::dataWillChange(const CharacterData& node)
+{
+    if (node == m_previousCaretNode) {
+        // This invalidation is eager, and intentionally uses stale state.
+        DisableCompositingQueryAsserts disabler;
+        m_caretBase->invalidateLocalCaretRect(m_previousCaretNode.get(), m_previousCaretRect);
+    }
+}
+
 void FrameSelection::paintCaret(GraphicsContext& context, const LayoutPoint& paintOffset)
 {
     if (selection().isCaret() && m_shouldPaintCaret) {