Avoid more temporary ranges in connection with various TextIterators.

Source/core/accessibility/AXRenderObject.cpp

 /*
 * Copyright (C) 2008 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
@@ skipping 1720 matching lines @@
     if (!allowsTextRanges() && !m_renderer->isText())
         return VisiblePosition();
 
     Node* node = m_renderer->node();
     if (!node)
         return VisiblePosition();
 
     if (index <= 0)
         return VisiblePosition(firstPositionInOrBeforeNode(node), DOWNSTREAM);
 
-    RefPtrWillBeRawPtr<Range> range = Range::create(m_renderer->document());
-    range->selectNodeContents(node, IGNORE_EXCEPTION);
-    CharacterIterator it(range.get());
+    Position start, end;
+    bool selected = Range::selectNodeContents(node, start, end);

[yosin_UTC9, 2014/09/12 01:02:24]

It seems utilizing |selected| makes cleaner.

if (!Range::selectNodeContens(...)) 
  return VisiblePosition();

[Mads Ager (chromium), 2014/09/12 10:52:08]

Done.

+    ASSERT_UNUSED(selected, selected);
+    CharacterIterator it(start, end);
     it.advance(index - 1);
-    return VisiblePosition(Position(it.range()->endContainer(), it.range()->endOffset(), Position::PositionIsOffsetInAnch\
-or), UPSTREAM);
+    return VisiblePosition(Position(it.endContainer(), it.endOffset(), Position::PositionIsOffsetInAnchor), UPSTREAM);
 }
 
 int AXRenderObject::indexForVisiblePosition(const VisiblePosition& pos) const
 {
     if (isNativeTextControl() && m_renderer->isTextControl()) {
         HTMLTextFormControlElement* textControl = toRenderTextControl(m_renderer)->textFormControlElement();
         return textControl->indexForVisiblePosition(pos);
     }
 
     if (!isTextControl())
@@ skipping 585 matching lines @@
         if (label && label->renderer()) {
             LayoutRect labelRect = axObjectCache()->getOrCreate(label)->elementRect();
             result.unite(labelRect);
         }
     }
 
     return result;
 }
 
 } // namespace blink