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

Source/core/editing/FrameSelection.cpp

 /*
  * Copyright (C) 2004, 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1440 matching lines @@
     LayoutRect drawingRect = localCaretRectWithoutUpdate();
     RenderObject* renderer = caretRenderer(node);
     if (renderer && renderer->isBox())
         toRenderBox(renderer)->flipForWritingMode(drawingRect);
     drawingRect.moveBy(roundedIntPoint(paintOffset));
     LayoutRect caret = intersection(drawingRect, clipRect);
     if (caret.isEmpty())
         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);
 
     context->fillRect(caret, caretColor);
 }
 
 void FrameSelection::debugRenderer(RenderObject *r, bool selected) const
 {
     if (r->node()->isElementNode()) {
         Element* element = static_cast<Element *>(r->node());
@@ skipping 593 matching lines @@
     sel.showTreeForThis();
 }
 
 void showTree(const WebCore::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
 }
 
 #endif