Refactor: Clear m_axObjectCache when AXObject detaches

Source/modules/accessibility/AXARIAGrid.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 19 matching lines @@
 #include "modules/accessibility/AXARIAGrid.h"
 
 #include "core/layout/LayoutObject.h"
 #include "modules/accessibility/AXObjectCacheImpl.h"
 #include "modules/accessibility/AXTableColumn.h"
 #include "modules/accessibility/AXTableRow.h"
 
 
 namespace blink {
 
-AXARIAGrid::AXARIAGrid(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+AXARIAGrid::AXARIAGrid(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
     : AXTable(layoutObject, axObjectCache)
 {
 }
 
 AXARIAGrid::~AXARIAGrid()
 {
 }
 
-PassRefPtr<AXARIAGrid> AXARIAGrid::create(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
+PassRefPtr<AXARIAGrid> AXARIAGrid::create(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
 {
     return adoptRef(new AXARIAGrid(layoutObject, axObjectCache));
 }
 
 bool AXARIAGrid::addTableCellChild(AXObject* child, HashSet<AXObject*>& appendedRows, unsigned& columnCount)
 {
     if (!child || !child->isTableRow() || child->ariaRoleAttribute() != RowRole)
         return false;
 
     AXTableRow* row = toAXTableRow(child);
@@ skipping 25 matching lines @@
 
     if (!isAXTable()) {
         AXLayoutObject::addChildren();
         return;
     }
 
     m_haveChildren = true;
     if (!m_layoutObject)
         return;
 
-    AXObjectCacheImpl* axCache = axObjectCache();
+    AXObjectCacheImpl& axCache = axObjectCache();
 
     // add only rows that are labeled as aria rows
     HashSet<AXObject*> appendedRows;
     unsigned columnCount = 0;
     for (RefPtr<AXObject> child = firstChild(); child; child = child->nextSibling()) {
 
         if (!addTableCellChild(child.get(), appendedRows, columnCount)) {
 
             // in case the layout tree doesn't match the expected ARIA hierarchy, look at the children
             if (!child->hasChildren())
                 child->addChildren();
 
             // The children of this non-row will contain all non-ignored elements (recursing to find them).
             // This allows the table to dive arbitrarily deep to find the rows.
             for (const auto& childObject : child->children())
                 addTableCellChild(childObject.get(), appendedRows, columnCount);
         }
     }
 
     // make the columns based on the number of columns in the first body
     for (unsigned i = 0; i < columnCount; ++i) {
-        AXTableColumn* column = toAXTableColumn(axCache->getOrCreate(ColumnRole));
+        AXTableColumn* column = toAXTableColumn(axCache.getOrCreate(ColumnRole));
         column->setColumnIndex((int)i);
         column->setParent(this);
         m_columns.append(column);
         if (!column->accessibilityIsIgnored())
             m_children.append(column);
     }
 
     AXObject* headerContainerObject = headerContainer();
     if (headerContainerObject && !headerContainerObject->accessibilityIsIgnored())
         m_children.append(headerContainerObject);
 }
 
 } // namespace blink