Change the caret color according to the lightness of the background color.

Source/core/editing/FrameSelection.cpp

Index: Source/core/editing/FrameSelection.cpp
diff --git a/Source/core/editing/FrameSelection.cpp b/Source/core/editing/FrameSelection.cpp
index 5a5f03ca12af958d053a017430e64f43cded1d55..229f473861437434ef32364958688bbf5d59dfa0 100644
--- a/Source/core/editing/FrameSelection.cpp
+++ b/Source/core/editing/FrameSelection.cpp
@@ -1458,7 +1458,13 @@ void CaretBase::paintCaret(Node* node, GraphicsContext* context, const LayoutPoi
         return;
 
     Color caretColor = Color::black;
-    Element* element = node->rootEditableElement();
+
+    Element* element;
+    if (node->isElementNode())
+        element = toElement(node);
+    else
+        element = node->parentElement();
+
     if (element && element->renderer())
         caretColor = element->renderer()->style()->visitedDependentColor(CSSPropertyColor);