Improve TypeError messages from failed array conversions.

Source/bindings/v8/custom/V8WindowCustom.cpp

Index: Source/bindings/v8/custom/V8WindowCustom.cpp
diff --git a/Source/bindings/v8/custom/V8WindowCustom.cpp b/Source/bindings/v8/custom/V8WindowCustom.cpp
index 957f27db2aad73763441e2b1686e1f45c23ce9d0..1ccee05bc0ec4cf73f34df7d64e0c653016fd961 100644
--- a/Source/bindings/v8/custom/V8WindowCustom.cpp
+++ b/Source/bindings/v8/custom/V8WindowCustom.cpp
@@ -266,7 +266,7 @@ void V8Window::postMessageMethodCustom(const v8::FunctionCallbackInfo<v8::Value>
         bool notASequence = false;
         if (!extractTransferables(args[transferablesArgIndex], portArray, arrayBufferArray, notASequence, args.GetIsolate())) {
             if (notASequence)
-                throwTypeError(ExceptionMessages::failedToExecute("postMessage", "Window", ExceptionMessages::notASequenceType(transferablesArgIndex == 1 ? "Second" : "Third")), args.GetIsolate());
+                throwTypeError(ExceptionMessages::failedToExecute("postMessage", "Window", ExceptionMessages::notASequenceTypeArgumentOrValue(transferablesArgIndex + 1)), args.GetIsolate());
             return;
         }
     }