PaymentRequest: The currencySystem should be non-nullable.

chrome/android/java/src/org/chromium/chrome/browser/payments/CurrencyFormatter.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.annotation.Nullable;
-
 import org.chromium.base.annotations.JNINamespace;
 
 import java.util.Locale;
 
 /**
  * Formatter for currency amounts.
  * https://w3c.github.io/browser-payment-api/specs/paymentrequest.html#currencyamount
  */
 @JNINamespace("payments")
 public class CurrencyFormatter {
     /**
      * Pointer to the native implementation.
      */
     private long mCurrencyFormatterAndroid;
 
     /**
      * Builds the formatter for the given currency code and the current user locale.
      *
      * @param currencyCode  The currency code. Most commonly, this follows ISO 4217 format: 3 upper
      *                      case ASCII letters. For example, "USD". Format is not restricted. Should
      *                      not be null.
      * @param currencySystem URI specifying the ISO4217 currency code specification. See for
      *          details: https://w3c.github.io/browser-payment-api/#paymentcurrencyamount-dictionary
-     *          Can be null, in which case "urn:iso:std:iso:4217" is assumed.
+     *          By default, the value is "urn:iso:std:iso:4217".
      * @param userLocale User's current locale. Should not be null.
      */
-    public CurrencyFormatter(
-            String currencyCode, @Nullable String currencySystem, Locale userLocale) {
+    public CurrencyFormatter(String currencyCode, String currencySystem, Locale userLocale) {
         assert currencyCode != null : "currencyCode should not be null";
+        assert currencySystem != null : "currencySystem should not be null";
         assert userLocale != null : "userLocale should not be null";
 
         // Note that this pointer could leak the native object. The called must call destroy() to
         // ensure that the native object is destroyed.
         mCurrencyFormatterAndroid = nativeInitCurrencyFormatterAndroid(
-                currencyCode, currencySystem == null ? "" : currencySystem, userLocale.toString());
+                currencyCode, currencySystem, userLocale.toString());
     }
 
     /** Will destroy the native object. This class shouldn't be used afterwards. */
     public void destroy() {
         if (mCurrencyFormatterAndroid != 0) {
             nativeDestroy(mCurrencyFormatterAndroid);
             mCurrencyFormatterAndroid = 0;
         }
     }
 
@@ skipping 17 matching lines @@
 
         return nativeFormat(mCurrencyFormatterAndroid, amountValue);
     }
 
     private native long nativeInitCurrencyFormatterAndroid(
             String currencyCode, String currencySystem, String localeName);
     private native void nativeDestroy(long nativeCurrencyFormatterAndroid);
     private native String nativeFormat(long nativeCurrencyFormatterAndroid, String amountValue);
     private native String nativeGetFormattedCurrencyCode(long nativeCurrencyFormatterAndroid);
 }