Cleanup <static_cast>: Switch to toFoo for Accessibility Objects.

Source/core/accessibility/AccessibilityARIAGrid.cpp

Index: Source/core/accessibility/AccessibilityARIAGrid.cpp
diff --git a/Source/core/accessibility/AccessibilityARIAGrid.cpp b/Source/core/accessibility/AccessibilityARIAGrid.cpp
index 73b2fb7f2b89753c1aa362a69f3e157c46325adf..bffabadf019d6be61b55ed1e3518e1302b3fa86a 100644
--- a/Source/core/accessibility/AccessibilityARIAGrid.cpp
+++ b/Source/core/accessibility/AccessibilityARIAGrid.cpp
@@ -57,7 +57,7 @@ bool AccessibilityARIAGrid::addTableCellChild(AccessibilityObject* child, HashSe
     if (!child || !child->isTableRow() || child->ariaRoleAttribute() != RowRole)
         return false;
 
-    AccessibilityTableRow* row = static_cast<AccessibilityTableRow*>(child);
+    AccessibilityTableRow* row = toAccessibilityTableRow(child);
     if (appendedRows.contains(row))
         return false;
 
@@ -117,7 +117,7 @@ void AccessibilityARIAGrid::addChildren()
 
     // make the columns based on the number of columns in the first body
     for (unsigned i = 0; i < columnCount; ++i) {
-        AccessibilityTableColumn* column = static_cast<AccessibilityTableColumn*>(axCache->getOrCreate(ColumnRole));
+        AccessibilityTableColumn* column = toAccessibilityTableColumn(axCache->getOrCreate(ColumnRole));
         column->setColumnIndex((int)i);
         column->setParent(this);
         m_columns.append(column);