Fix leaking AXNodeObjects when sub document detaches

third_party/WebKit/Source/modules/accessibility/AXSlider.cpp

 /*
  * Copyright (C) 2009 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 69 matching lines @@
     case MediaVolumeSliderPart:
         return AccessibilityOrientationVertical;
 
     default:
         return AccessibilityOrientationHorizontal;
     }
 }
 
 void AXSlider::addChildren()
 {
+    ASSERT(!isDetached());
     ASSERT(!m_haveChildren);
 
     m_haveChildren = true;
 
     AXObjectCacheImpl& cache = axObjectCache();
 
     AXSliderThumb* thumb = static_cast<AXSliderThumb*>(cache.getOrCreate(SliderThumbRole));
     thumb->setParent(this);
 
     // Before actually adding the value indicator to the hierarchy,
@@ skipping 58 matching lines @@
         return LayoutRect();
     return toElement(sliderLayoutObject->node())->userAgentShadowRoot()->getElementById(ShadowElementNames::sliderThumb())->boundingBox();
 }
 
 bool AXSliderThumb::computeAccessibilityIsIgnored(IgnoredReasons* ignoredReasons) const
 {
     return accessibilityIsIgnoredByDefault(ignoredReasons);
 }
 
 } // namespace blink