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 02fd9921d87ecfd72dc766d6b7e02429d59dab69..e19f7cfd33a16e8947b7e9b36a9aef7cb2f98ee2 100644
--- a/third_party/WebKit/Source/core/editing/FrameSelection.cpp
+++ b/third_party/WebKit/Source/core/editing/FrameSelection.cpp
@@ -731,6 +731,15 @@ 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) {