[Payments] Cache payment manifests.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentManifestWebDataService.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentManifestWebDataService.java b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentManifestWebDataService.java
new file mode 100644
index 0000000000000000000000000000000000000000..757261ead3d69aeb86666261dec61ade8ef21b20
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentManifestWebDataService.java
@@ -0,0 +1,119 @@
+// Copyright 2017 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.base.ThreadUtils;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.payments.mojom.WebAppManifestSection;
+
+/** Java wrapper of the payment manifest web data service. */
+@JNINamespace("payments")
+public class PaymentManifestWebDataService {
+    /** Interface for the callback to invoke when getting data from the web data service. */
+    public interface PaymentManifestWebDataServiceCallback {
+        /**
+         * Called when getPaymentMethodManifest success.
+         *
+         * @param webAppsIds The web apps Ids in the payment method manifest.
+         */
+        @CalledByNative("PaymentManifestWebDataServiceCallback")
+        void onPaymentMethodManifestFetched(String[] webAppsIds);
+
+        /**
+         * Called when getPaymentWebAppManifest success.
+         *
+         * @param manifest The web app manifest sections.
+         */
+        @CalledByNative("PaymentManifestWebDataServiceCallback")
+        void onPaymentWebAppManifestFetched(WebAppManifestSection[] manifest);

[please use gerrit instead, 2017/04/24 18:22:31]

Can you define a simpler interface that hides the fact that you have two tables?

It would be preferable to query for payment method name and get back a list of
(package_mame, min_version, fingerprints) tuples.

Similarly, it would be preferable to define a single call to store this
information on disk: saveManifests(manifests), where each item in the
|manifests| is a (method_mame, package_mame, min_version, fingerprints) tuple.

[gogerald1, 2017/04/26 13:46:31]

Distinguish them looks a little more consistent here since we distinguished them
in PaymentManifestDownloader and PaymentManifestParser.

Moreover, query payment method manifest only is faster so as to switch to
download manifest online quicker for the first time.

Make sense? We could also modify it later given this CL is already big.

[please use gerrit instead, 2017/04/26 15:00:43]

You're right that PaymentManifestDownloader has two methods used in sequence
that could be abstracted into a single method instead
(downloadPaymentMethodManifest() and downloadWebAppManifest()).

However, PaymentManifestDownloader performs two downloads when looking for
payment method manifest: One HTTP HEAD download payment method name and one GET
download for the actual JSON file with payment method information. This is
abstracted away behind a single call downloadPaymentMethodManifest().

There's a fine line between exposing and abstracting parts of the
implementation. I will let you use your own judgement here.
This argument makes sense.

[gogerald1, 2017/04/26 17:30:30]

Acknowledged.

+    }
+
+    private static PaymentManifestWebDataService sWebDataService;
+
+    /**
+     * Gets an instance of this class.
+     *
+     * @return An instance of PaymentManifestWebDataService.
+     */
+    public static PaymentManifestWebDataService getInstance() {
+        ThreadUtils.assertOnUiThread();
+        if (sWebDataService == null) {
+            sWebDataService = new PaymentManifestWebDataService();
+        }
+        return sWebDataService;
+    }
+
+    private final long mManifestWebDataServiceAndroid;

[please use gerrit instead, 2017/04/24 18:22:31]

Please put all member variables together.

[gogerald1, 2017/04/26 13:46:31]

Done.

+
+    private PaymentManifestWebDataService() {
+        mManifestWebDataServiceAndroid = nativeInit();
+    }
+
+    /**
+     * Gets the payment method's manifest.
+     *
+     * @param methodName The payment method name.
+     * @param callback   The callback to invoke when finishing the request.
+     * @return True if the result will be returned through callback.
+     */
+    public boolean getPaymentMethodManifest(
+            String methodName, PaymentManifestWebDataServiceCallback callback) {
+        return nativeGetPaymentMethodManifest(mManifestWebDataServiceAndroid, methodName, callback);
+    }
+
+    /**
+     * Adds the supported web apps Ids of the method.

[please use gerrit instead, 2017/04/24 18:22:31]

s/web app Ids/Android app package names/g

Here and everywhere.

[gogerald1, 2017/04/26 13:46:32]

Done.

+     *
+     * @param methodName The method name.
+     * @param webAppsIds The supported web apps Ids.
+     */
+    public void addPaymentMethodManifest(String methodName, String[] webAppsIds) {
+        nativeAddPaymentMethodManifest(mManifestWebDataServiceAndroid, methodName, webAppsIds);
+    }
+
+    /**
+     * Gets the payment web app's manifest.
+     *
+     * @param webAppId The id of the payment web app.

[please use gerrit instead, 2017/04/24 18:22:31]

s/webAppId/androidAppPackageName/ (or packageName)

It's verify confusing to talk about web app identifiers when dealing with
Android payment apps.

[gogerald1, 2017/04/26 13:46:31]

Done.

+     * @param callback The callback to invoke when finishing the request.
+     * @return True if the result will be returned through callback.
+     */
+    public boolean getPaymentWebAppManifest(
+            String webAppId, PaymentManifestWebDataServiceCallback callback) {
+        return nativeGetPaymentWebAppManifest(mManifestWebDataServiceAndroid, webAppId, callback);
+    }
+
+    @CalledByNative
+    private static WebAppManifestSection[] createManifest(int numberOfsections) {
+        return new WebAppManifestSection[numberOfsections];
+    }
+
+    @CalledByNative
+    private static void addSectionToManifest(WebAppManifestSection[] manifest, int sectionIndex,
+            String id, long minVersion, int numberOfFingerprints) {
+        manifest[sectionIndex] = new WebAppManifestSection();
+        manifest[sectionIndex].id = id;
+        manifest[sectionIndex].minVersion = minVersion;
+        manifest[sectionIndex].fingerprints = new byte[numberOfFingerprints][];
+    }
+
+    @CalledByNative
+    private static void addFingerprintToSection(WebAppManifestSection[] manifest, int sectionIndex,
+            int fingerprintIndex, byte[] fingerprint) {
+        manifest[sectionIndex].fingerprints[fingerprintIndex] = fingerprint;
+    }
+
+    private native long nativeInit();

[please use gerrit instead, 2017/04/24 18:22:31]

If there's initialization, then you also need destruction to avoid leaking
stuff.

[gogerald1, 2017/04/26 13:46:31]

Done.

+    private native boolean nativeGetPaymentMethodManifest(
+            long nativePaymentManifestWebDataServiceAndroid, String methodName,
+            PaymentManifestWebDataServiceCallback callback);
+    private native void nativeAddPaymentMethodManifest(
+            long nativePaymentManifestWebDataServiceAndroid, String methodName,
+            String[] webAppsIds);
+    private native boolean nativeGetPaymentWebAppManifest(

[please use gerrit instead, 2017/04/24 18:22:31]

Can you group the "Get" methods together?

[gogerald1, 2017/04/26 13:46:32]

Done.

+            long nativePaymentManifestWebDataServiceAndroid, String webAppId,
+            PaymentManifestWebDataServiceCallback callback);
+}