Java implementation of PaymentRequest mojo service

chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentApp.java

Index: chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentApp.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentApp.java b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentApp.java
new file mode 100644
index 0000000000000000000000000000000000000000..e632ce9ee6159abea09bfe7b8e529e655b2731e7
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+++ b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentApp.java
@@ -0,0 +1,58 @@
+// 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 org.chromium.chrome.browser.payments.ui.LineItem;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+
+/**
+ * The interface that a payment app implements. A payment app can get its data from Chrome autofill,
+ * Android Pay, or third party apps.
+ */
+public interface PaymentApp {
+    /**
+     * The interface for the requester of instruments.
+     */
+    public interface InstrumentsCallback {
+        /**
+         * Called by this app to provide a list of instruments asynchronously.
+         *
+         * @param app The calling app.
+         * @param instruments The instruments from this app.
+         */
+        void onInstrumentsReady(PaymentApp app, List<PaymentInstrument> instruments);
+    }
+
+    /**
+     * Provides a list of all payment instruments in this app. For example, this can be all credit
+     * cards for the current profile. Can return null or empty list, e.g., if user has no locally
+     * stored credit cards.
+     *
+     * @param items The line items in the payment request. Can be used to filter out instruments
+     * that, for example, do not have enough funds.
+     * @param callback The object that will receive the list of instruments.
+     */
+    void getInstruments(ArrayList<LineItem> items, InstrumentsCallback callback);

[Ted C, 2016/04/22 03:59:37]

any reason we don't use vanilla List here?

[please use gerrit instead, 2016/04/25 19:22:30]

Was ensuring O(1) random access, until you assured me that our code already uses
ArrayList everywhere as a rule of thumb.

+
+    /**
+     * Returns a list of all payment method names that this app supports. For example, ["visa",
+     * "mastercard"] in basic card payments. Should return a list of at least one method name.
+     * https://w3c.github.io/browser-payment-api/specs/basic-card-payment.html#method-id
+     *
+     * @return The list of all payment method names that this app supports.
+     */
+    HashSet<String> getSupportedMethodNames();

[Ted C, 2016/04/22 03:59:37]

same thing...should use a vanilla Set if we can.

[please use gerrit instead, 2016/04/25 19:22:30]

Done.

+
+    /**
+     * Returns the identifier for this payment app to be saved in user preferences. For example,
+     * this can be "autofill", "https://android.com/pay", or "com.example.app.ExamplePaymentApp".
+     *
+     * @return The identifier for this payment app.
+     */
+    String getIdentifier();
+}