Add unit test for providing empty list of detail items

third_party/WebKit/Source/modules/payments/PaymentDetailsTestHelper.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/payments/PaymentDetailsTestHelper.h"
 
 #include "modules/payments/CurrencyAmount.h"
 #include "platform/heap/HeapAllocator.h"
 
 namespace blink {
@@ skipping 75 matching lines @@
     else
         item = buildPaymentItemForTest();
 
     ShippingOption shippingOption;
     if (detail == PaymentTestDetailShippingOption)
         shippingOption = buildShippingOptionForTest(data, modificationType, valueToUse);
     else
         shippingOption = buildShippingOptionForTest();
 
     PaymentDetails result;
-    result.setItems(HeapVector<PaymentItem>(1, item));
+    if (detail == PaymentTestDetailNoItems)
+        result.setItems(HeapVector<PaymentItem>());
+    else
+        result.setItems(HeapVector<PaymentItem>(1, item));
     result.setShippingOptions(HeapVector<ShippingOption>(2, shippingOption));
 
     return result;
 }
 
 } // namespace blink