PaymentApp: Add classes for supporting Web Based Payment Apps

chrome/android/java/src/org/chromium/chrome/browser/payments/WebBasedPaymentAppBridge.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.graphics.drawable.Drawable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Native bridge for interacting with web based payment apps.
+ */
+public class WebBasedPaymentAppBridge {
+    /**
+     * This class represents a payment app manifest as defined in the Payment
+     * App API specification.
+     *
+     * @see https://w3c.github.io/webpayments-payment-apps-api/#payment-app-manifest
+     */
+    public class Manifest {

[agrieve, 2016/11/28 17:59:53]

Should these inner classes be static? 

[tommyt, 2016/11/30 13:44:38]

Done.

+        public String id;

[please use gerrit instead, 2016/11/29 14:28:44]

Manifest does not have an ID field.

[tommyt, 2016/11/30 13:44:38]

True, but the Payment App does have an ID, and I think we need to know this
AppID in Chrome too. At the moment, I only use it to create a unique id for a
ServiceWorkerPaymentInstrument, but I think we're also going to need to use this
AppID to identify the app when we start actually invoking service workers. 

I felt this was a suitable place to put it. It would also be possible to keep it
outside of this class, but then I would need to introduce another class that
would keep track of this ID along with a reference to the manifest;

public class AppEntry {
    public String id;
    public Manifest manifest;
}

This would be a bit more cumbersome, and I don't think it's that crucial that
the Manifest class matches the W3C PaymentAppManifest definition exactly. What
do you think?

[zino, 2016/11/30 14:04:46]

IMHO, you can rename the field to scopeUrl and then leave a comment for it.

[tommyt, 2016/11/30 14:14:00]

This sounds like a good idea. Maybe this is better naming for this field. If
rouslan agrees, I can change this to "scopeUrl"

[please use gerrit instead, 2016/11/30 15:08:28]

+1 

[tommyt, 2016/12/01 13:55:49]

Done.

+        public String label;
+        public Drawable icon;
+        public List<Option> options = new ArrayList<>();
+    }
+
+    /**
+     * This class represents a payment option as defined in the Payment App API
+     * specification.
+     *
+     * @see https://w3c.github.io/webpayments-payment-apps-api/#payment-app-options
+     */
+    public class Option {
+        public String id;
+        public String label;
+        public Drawable icon;
+        public List<String> enabledMethods = new ArrayList<>();
+    }
+
+    /**
+     * Get a list of all the installed app manifests.
+     */
+    public List<Manifest> getAllAppManifests() {
+        // Not yet implemented

[please use gerrit instead, 2016/11/29 14:28:44]

Add a TODO.

[tommyt, 2016/11/30 13:44:38]

Done.

+        return new ArrayList<Manifest>();
+    }
+}