Refactor: Clear m_axObjectCache when AXObject detaches

Source/modules/accessibility/AXTableCell.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 19 matching lines @@
 #include "modules/accessibility/AXTableCell.h"
 
 #include "core/layout/LayoutTableCell.h"
 #include "modules/accessibility/AXObjectCacheImpl.h"
 
 
 namespace blink {
 
 using namespace HTMLNames;
 
-AXTableCell::AXTableCell(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+AXTableCell::AXTableCell(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
     : AXLayoutObject(layoutObject, axObjectCache)
 {
 }
 
 AXTableCell::~AXTableCell()
 {
 }
 
-PassRefPtr<AXTableCell> AXTableCell::create(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+PassRefPtr<AXTableCell> AXTableCell::create(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
 {
     return adoptRef(new AXTableCell(layoutObject, axObjectCache));
 }
 
 bool AXTableCell::isTableHeaderCell() const
 {
     return node() && node()->hasTagName(thTag);
 }
 
 bool AXTableCell::isRowHeaderCell() const
@@ skipping 21 matching lines @@
 
     return false;
 }
 
 AXObject* AXTableCell::parentTable() const
 {
     if (!m_layoutObject || !m_layoutObject->isTableCell())
         return 0;
 
     // If the document no longer exists, we might not have an axObjectCache.
-    if (!axObjectCache())
+    if (isDetached())
         return 0;
 
     // Do not use getOrCreate. parentTable() can be called while the layout tree is being modified
     // by javascript, and creating a table element may try to access the layout tree while in a bad state.
     // By using only get() implies that the AXTable must be created before AXTableCells. This should
     // always be the case when AT clients access a table.
     // https://bugs.webkit.org/show_bug.cgi?id=42652
-    return axObjectCache()->get(toLayoutTableCell(m_layoutObject)->table());
+    return axObjectCache().get(toLayoutTableCell(m_layoutObject)->table());
 }
 
 bool AXTableCell::isTableCell() const
 {
     AXObject* parent = parentObjectUnignored();
     if (!parent || !parent->isTableRow())
         return false;
 
     return true;
 }
@@ skipping 135 matching lines @@
         return 0;
 
     LayoutTableCell* headerCell = section->primaryCellAt(row, 0);
     if (!headerCell || headerCell == layoutCell)
         return 0;
 
     Node* cellElement = headerCell->node();
     if (!cellElement || !cellElement->hasTagName(thTag))
         return 0;
 
-    return axObjectCache()->getOrCreate(headerCell);
+    return axObjectCache().getOrCreate(headerCell);
 }
 
 } // namespace blink