[PaymentReqeust] Add error message in PaymentDetails. (in blink side)

third_party/WebKit/Source/modules/payments/PaymentsValidators.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/PaymentsValidators.h"
 
 #include "bindings/core/v8/ScriptRegexp.h"
 #include "wtf/text/StringImpl.h"
 
 namespace blink {
 
-// We limit the maximum length of the currency code to 2048 bytes for security reasons.
-static const int maxCurrencyCodeLength = 2048;
+// We limit the maximum length of string to 2048 bytes for security reasons.
+static const int maxiumStringLength = 2048;
 
 bool PaymentsValidators::isValidCurrencyCodeFormat(const String& code, String* optionalErrorMessage)
 {
-    if (code.length() <= maxCurrencyCodeLength)
+    if (code.length() <= maxiumStringLength)
         return true;
 
     if (optionalErrorMessage)
         *optionalErrorMessage = "The currency code should be at most 2048 characters long";
 
     return false;
 }
 
 bool PaymentsValidators::isValidAmountFormat(const String& amount, String* optionalErrorMessage)
 {
@@ skipping 53 matching lines @@
     if (address->language_code.isEmpty() && !address->script_code.isEmpty()) {
         if (optionalErrorMessage)
             *optionalErrorMessage = "If language code is empty, then script code should also be empty";
 
         return false;
     }
 
     return true;
 }
 
+bool PaymentsValidators::isValidErrorMsgFormat(const String& error, String* optionalErrorMessage)
+{
+    if (error.length() <= maxiumStringLength)
+        return true;
+
+    if (optionalErrorMessage)
+        *optionalErrorMessage = "Error message should be at most 2048 characters long";
+
+    return false;
+}
+
 } // namespace blink