Make SurroundingText work for a Range.

Source/web/WebSurroundingText.cpp

 /*
  * Copyright (C) 2012 Google 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 37 matching lines @@
     m_private.reset(new SurroundingText(VisiblePosition(node->renderer()->positionForPoint(static_cast<IntPoint>(nodePoint))).deepEquivalent().parentAnchoredEquivalent(), maxLength));
 }
 
 WebString WebSurroundingText::textContent() const
 {
     return m_private->content();
 }
 
 size_t WebSurroundingText::hitOffsetInTextContent() const
 {
-    return m_private->positionOffsetInContent();
+    ASSERT(m_private->startOffsetInContent() == m_private->endOffsetInContent());
+    return m_private->startOffsetInContent();
 }
 
 WebRange WebSurroundingText::rangeFromContentOffsets(size_t startOffsetInContent, size_t endOffsetInContent)
 {
     return m_private->rangeFromContentOffsets(startOffsetInContent, endOffsetInContent);
 }
 
 bool WebSurroundingText::isNull() const
 {
     return !m_private.get();
 }
 
 void WebSurroundingText::reset()
 {
     m_private.reset(0);
 }
 
 } // namespace blink