PaymentRequest: The currencySystem should be non-nullable.

chrome/android/javatests/src/org/chromium/chrome/browser/payments/CurrencyFormatterTest.java

 // 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.
 
 package org.chromium.chrome.browser.payments;
 
 import android.support.test.filters.MediumTest;
 
 import junit.framework.Assert;
 
@@ skipping 80 matching lines @@
         for (int i = 0; i < testCases.size(); i++) {
             Object[] testCase = testCases.get(i);
 
             String amount = (String) testCase[0];
             String currency = (String) testCase[1];
             String locale = (String) testCase[2];
             String expectedCurrencyFormatting = (String) testCase[3];
             String expectedAmountFormatting = (String) testCase[4];
 
             CurrencyFormatter formatter =
-                    new CurrencyFormatter(currency, null, LocaleUtils.forLanguageTag(locale));
+                    new CurrencyFormatter(currency, "", LocaleUtils.forLanguageTag(locale));
 
             String formattedAmount = formatter.format(amount).replace(SPACE, " ");
             Assert.assertEquals("\"" + currency + "\" \"" + amount + "\" (\"" + locale
                             + "\" locale) should be formatted into \"" + expectedAmountFormatting
                             + "\"",
                     expectedAmountFormatting, formattedAmount);
             Assert.assertEquals("\"" + currency + "\""
                             + " should be formatted into \"" + expectedCurrencyFormatting + "\"",
                     expectedCurrencyFormatting, formatter.getFormattedCurrencyCode());
         }
     }
 }