Cleanup: Start using toFoo methods as part of newly adopted coding guideline.

Source/core/accessibility/AccessibilityARIAGridCell.cpp

Index: Source/core/accessibility/AccessibilityARIAGridCell.cpp
diff --git a/Source/core/accessibility/AccessibilityARIAGridCell.cpp b/Source/core/accessibility/AccessibilityARIAGridCell.cpp
index 201aef628165961af23e9d08d562e682d930f39e..c2c17a238519083b331a5bf29d91470cfbe2c0f7 100644
--- a/Source/core/accessibility/AccessibilityARIAGridCell.cpp
+++ b/Source/core/accessibility/AccessibilityARIAGridCell.cpp
@@ -81,7 +81,7 @@ void AccessibilityARIAGridCell::rowIndexRange(pair<unsigned, unsigned>& rowRange
     } else if (parent->isAccessibilityTable()) {
         // We reached the parent table, so we need to inspect its
         // children to determine the row index for the cell in it.
-        unsigned columnCount = static_cast<AccessibilityTable*>(parent)->columnCount();
+        unsigned columnCount = toAccessibilityTable(parent)->columnCount();
         if (!columnCount)
             return;