Refactor: Clear m_axObjectCache when AXObject detaches

Source/modules/accessibility/AXTableRow.h

 /*
  * 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 20 matching lines @@
 
 #include "modules/accessibility/AXLayoutObject.h"
 
 namespace blink {
 
 class AXObjectCacheImpl;
 
 class AXTableRow : public AXLayoutObject {
 
 protected:
-    AXTableRow(LayoutObject*, AXObjectCacheImpl*);
+    AXTableRow(LayoutObject*, AXObjectCacheImpl&);
 
 public:
-    static PassRefPtr<AXTableRow> create(LayoutObject*, AXObjectCacheImpl*);
+    static PassRefPtr<AXTableRow> create(LayoutObject*, AXObjectCacheImpl&);
     virtual ~AXTableRow();
 
     virtual bool isTableRow() const override final;
 
     // retrieves the "row" header (a th tag in the rightmost column)
     virtual AXObject* headerObject();
     // retrieves the "row" headers (th, scope) from left to right for the each row.
     virtual void headerObjectsForRow(AccessibilityChildrenVector&);
     AXObject* parentTable() const;
 
@@ skipping 11 matching lines @@
     int m_rowIndex;
 
     virtual bool computeAccessibilityIsIgnored(IgnoredReasons* = nullptr) const override final;
 };
 
 DEFINE_AX_OBJECT_TYPE_CASTS(AXTableRow, isTableRow());
 
 } // namespace blink
 
 #endif // AXTableRow_h