Duplicate shipping option identifiers should throw TypeError.

third_party/WebKit/Source/modules/payments/PaymentRequest.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/PaymentRequest.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/JSONValuesForV8.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "bindings/core/v8/ScriptState.h"
@@ skipping 188 matching lines @@
 {
     for (const auto& item : items) {
         validateShippingOptionOrPaymentItem(item, exceptionState);
         if (exceptionState.hadException())
             return;
     }
 }
 
 void validateShippingOptions(const HeapVector<PaymentShippingOption>& options, ExceptionState& exceptionState)
 {
+    HashSet<String> uniqueIds;
     for (const auto& option : options) {
         if (!option.hasId() || option.id().isEmpty()) {
             exceptionState.throwTypeError("ShippingOption id required");
             return;
         }

[please use gerrit instead, 2016/07/12 10:01:16]

nit: newline between the blocks.

+        if (uniqueIds.contains(option.id())) {
+            exceptionState.throwTypeError("Duplicate shipping option identifiers are not allowed");
+            return;
+        }
+        uniqueIds.add(option.id());
 
         validateShippingOptionOrPaymentItem(option, exceptionState);
         if (exceptionState.hadException())
             return;
     }
 }
 
 void validatePaymentDetailsModifiers(const HeapVector<PaymentDetailsModifier>& modifiers, ExceptionState& exceptionState)
 {
     if (modifiers.isEmpty()) {
@@ skipping 400 matching lines @@
 {
     m_completeResolver.clear();
     m_showResolver.clear();
     m_abortResolver.clear();
     if (m_clientBinding.is_bound())
         m_clientBinding.Close();
     m_paymentProvider.reset();
 }
 
 } // namespace blink