Move Position::isRenderedCharacter() for Text node to LayoutText

Source/core/layout/LayoutText.cpp

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 1116 matching lines @@
         }
         return true;
     }
     for (unsigned i = 0; i < length; ++i) {
         if (!style()->isCollapsibleWhiteSpace(characters16()[i]))
             return false;
     }
     return true;
 }
 
+bool LayoutText::isRenderedCharacter(int offsetInNode) const
+{
+    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
+        if (offsetInNode < static_cast<int>(box->start()) && !containsReversedText()) {
+            // The offset we're looking for is before this node
+            // this means the offset must be in content that is
+            // not laid out. Return false.
+            return false;
+        }
+        if (offsetInNode >= static_cast<int>(box->start()) && offsetInNode < static_cast<int>(box->start() + box->len()))
+            return true;
+    }
+
+    return false;
+}
+
 bool LayoutText::containsOnlyWhitespace(unsigned from, unsigned len) const
 {
     ASSERT(m_text);
     StringImpl& text = *m_text.impl();
     unsigned currPos;
     for (currPos = from;
     currPos < from + len && (text[currPos] == newlineCharacter || text[currPos] == spaceCharacter || text[currPos] == tabulationCharacter);
     currPos++) { }
     return currPos >= (from + len);
 }
@@ skipping 713 matching lines @@
     for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
         paintInvalidationContainer.invalidateDisplayItemClientOnBacking(*box);
         if (box->truncation() != cNoTruncation) {
             if (EllipsisBox* ellipsisBox = box->root().ellipsisBox())
                 paintInvalidationContainer.invalidateDisplayItemClientOnBacking(*ellipsisBox);
         }
     }
 }
 
 } // namespace blink