Fix bug in BackwardsCharacterIterator::endPosition introduced in latest change.

Source/core/editing/TextIterator.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov.
  *
  * 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
@@ skipping 1715 matching lines @@
             r->setStart(n, offset - 1, ASSERT_NO_EXCEPTION);
             r->setEnd(n, offset, ASSERT_NO_EXCEPTION);
         }
     }
     return r.release();
 }
 
 Position BackwardsCharacterIterator::endPosition() const
 {
     Node* n = m_textIterator.startContainer();
-    if (m_textIterator.atEnd()) {
+    if (!m_textIterator.atEnd()) {
         if (m_textIterator.length() > 1)
             return createLegacyEditingPosition(n, m_textIterator.endOffset() - m_runOffset);
         ASSERT(!m_runOffset);
     }
     return createLegacyEditingPosition(n, m_textIterator.endOffset());
 }
 
 void BackwardsCharacterIterator::advance(int count)
 {
     if (count <= 0) {
@@ skipping 576 matching lines @@
             resultEnd = collapseTo;
             return;
         }
     }
 
     CharacterIterator computeRangeIterator(inputStart, inputEnd, iteratorFlagsForFindPlainText);
     calculateCharacterSubrange(computeRangeIterator, matchStart, matchLength, resultStart, resultEnd);
 }
 
 }