Support union return type for anonymous named/indexed getter

Source/wtf/UnionType.h

Index: Source/wtf/UnionType.h
diff --git a/Source/wtf/text/StringStatics.h b/Source/wtf/UnionType.h
similarity index 64%
copy from Source/wtf/text/StringStatics.h
copy to Source/wtf/UnionType.h
index 73097bc5cdbaf2e17318bd93cdcb1c445f676b27..23597ca6e3149486641e9332921304c8eeb90269 100644
--- a/Source/wtf/text/StringStatics.h
+++ b/Source/wtf/UnionType.h
@@ -28,19 +28,50 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef StringStatics_h
-#define StringStatics_h
+#ifndef UnionType_h
+#define UnionType_h
 
 namespace WTF {
 
-class StringStatics {
+// UnionTypeN holds multiple types of objects.
+//
+// WebIDL(UnionType):
+// http://www.w3.org/TR/WebIDL/#prod-UnionType
+//
+// Example IDL:
+// http://www.whatwg.org/specs/web-apps/current-work/multipage/common-dom-interfaces.html#htmlformcontrolscollection
+template<typename Type1, typename Type2>
+class UnionType2 {
 public:
-    static void init();
-
+    UnionType2()
+    {
+    }
+    explicit UnionType2(PassRefPtr<Type1> value)
+    {
+        m_value1 = value;
+    }
+    explicit UnionType2(PassRefPtr<Type2> value)
+    {
+        m_value2 = value;
+    }
+    bool isNull() const
+    {
+        return !m_value1 && !m_value2;
+    }
+    PassRefPtr<Type1> member1() const
+    {
+        return m_value1;
+    }
+    PassRefPtr<Type2> member2() const
+    {
+        return m_value2;
+    }
 private:
-    StringStatics();
+    RefPtr<Type1> m_value1;
+    RefPtr<Type2> m_value2;
 };
 
-}
 
-#endif
+} // namespace WTF
+
+#endif // UnionType_h