[Payments] Add information requested by merchant metrics to PR.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestMetrics.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestMetrics.java b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestMetrics.java
new file mode 100644
index 0000000000000000000000000000000000000000..f7b52acaa4ca394e277cb51fc22fc329f5098fba
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestMetrics.java
@@ -0,0 +1,63 @@
+// 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.base.metrics.RecordHistogram;
+
+/**
+ * A class used to record metrics for the Payment Request feature.
+ */
+public final class PaymentRequestMetrics {
+
+    // PaymentRequestRequestedInformation defined in tools/metrics/histograms/histograms.xml.
+    public static final int REQUESTED_INFORMATION_NONE = 0;

[please use gerrit instead, 2016/07/27 16:24:40]

Put @VisibleForTesting on all of these constants.

All public constants need Javadoc.

[sebsg, 2016/07/27 17:26:01]

Done.

+    public static final int REQUESTED_INFORMATION_EMAIL = 1;
+    public static final int REQUESTED_INFORMATION_PHONE = 2;
+    public static final int REQUESTED_INFORMATION_SHIPPING = 3;
+    public static final int REQUESTED_INFORMATION_EMAIL_PHONE = 4;
+    public static final int REQUESTED_INFORMATION_EMAIL_SHIPPING = 5;
+    public static final int REQUESTED_INFORMATION_PHONE_SHIPPING = 6;
+    public static final int REQUESTED_INFORMATION_EMAIL_PHONE_SHIPPING = 7;
+    public static final int REQUESTED_INFORMATION_MAX = 8;
+
+    // There should be no instance of PaymentRequestMetrics created.
+    private PaymentRequestMetrics() {};
+
+    public static void recordRequestedInformationHistogram(boolean requestEmail,

[please use gerrit instead, 2016/07/27 16:24:40]

All public functions need Javadoc.

[sebsg, 2016/07/27 17:26:01]

Done.

+            boolean requestPhone, boolean requestShipping) {
+        int requestInformation;
+        if (requestEmail) {

[please use gerrit instead, 2016/07/27 16:24:40]

The simpler way to map 3 booleans to a number: consider them bits. You will need
to re-order a little, however.

  shipping=4 phone=2 email=1
     0         0       0      NONE=0
     0         0       1      EMAIL=1
     0         1       0      PHONE=2
     0         1       1      PHONE_EMAIL=3
     1         0       0      SHIPPING=4
     1         0       1      SHIPPING_EMAIL=5
     1         1       0      SHIPPING_PHONE=6
     1         1       1      SHIPPING_PHONE_EMAIL=7

Then your function can be simpler:

int requestInformation =
        (requestEmail ? 1 : 0) +
        (requestPhone ? 2 : 0) +
        (requestShipping ? 4 : 0);

[sebsg, 2016/07/27 17:26:01]

Nice thanks!

+            if (requestPhone) {
+                if (requestShipping) {
+                    requestInformation = REQUESTED_INFORMATION_EMAIL_PHONE_SHIPPING;
+                } else {
+                    requestInformation = REQUESTED_INFORMATION_EMAIL_PHONE;
+                }
+            } else {
+                if (requestShipping) {
+                    requestInformation = REQUESTED_INFORMATION_EMAIL_SHIPPING;
+                } else {
+                    requestInformation = REQUESTED_INFORMATION_EMAIL;
+                }
+            }
+        } else {
+            if (requestPhone) {
+                if (requestShipping) {
+                    requestInformation = REQUESTED_INFORMATION_PHONE_SHIPPING;
+                } else {
+                    requestInformation = REQUESTED_INFORMATION_PHONE;
+                }
+            } else {
+                if (requestShipping) {
+                    requestInformation = REQUESTED_INFORMATION_SHIPPING;
+                } else {
+                    requestInformation = REQUESTED_INFORMATION_NONE;
+                }
+            }
+        }
+        RecordHistogram.recordEnumeratedHistogram("PaymentRequest.RequestedInformation",
+                requestInformation, REQUESTED_INFORMATION_MAX);
+    }
+}