Revert 146726 "AXObjectCache gets recreated during document tear..."

Source/WebCore/html/RangeInputType.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2011 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 228 matching lines @@
     else
         return; // Did not match any key binding.
 
     newValue = stepRange.clampValue(newValue);
 
     if (newValue != current) {
         EventQueueScope scope;
         TextFieldEventBehavior eventBehavior = DispatchChangeEvent;
         setValueAsDecimal(newValue, eventBehavior, IGNORE_EXCEPTION);
 
-        if (AXObjectCache* cache = element()->document()->existingAXObjectCache())
-            cache->postNotification(element(), AXObjectCache::AXValueChanged, true);
+        if (AXObjectCache::accessibilityEnabled())
+            element()->document()->axObjectCache()->postNotification(element(), AXObjectCache::AXValueChanged, true);
         element()->dispatchFormControlChangeEvent();
     }
 
     event->setDefaultHandled();
 }
 
 void RangeInputType::createShadowSubtree()
 {
     ASSERT(element()->shadow());
 
@@ skipping 143 matching lines @@
     }
     const Decimal closestLeft = middle ? m_tickMarkValues[middle - 1] : Decimal::infinity(Decimal::Negative);
     const Decimal closestRight = middle != m_tickMarkValues.size() ? m_tickMarkValues[middle] : Decimal::infinity(Decimal::Positive);
     if (closestRight - value < value - closestLeft)
         return closestRight;
     return closestLeft;
 }
 #endif
 
 } // namespace WebCore