[Payments] Add Payment Request journey metrics.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestJourneyLogger.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestJourneyLogger.java b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestJourneyLogger.java
new file mode 100644
index 0000000000000000000000000000000000000000..35c1d5cdaee0f86062a5b841b0a565be0c8c7f2b
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestJourneyLogger.java
@@ -0,0 +1,134 @@
+// 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 journey metrics for the Payment Request feature.
+ */
+public class PaymentRequestJourneyLogger {
+    public static final int SECTION_CONTACT_INFO = 0;
+    public static final int SECTION_CREDIT_CARDS = 1;
+    public static final int SECTION_SHIPPING_ADDRESS = 2;
+    public static final int SECTION_MAX = 3;
+
+    private static final int MIN_EXPECTED_SAMPLE = 0;
+    private static final int MAX_EXPECTED_SAMPLE = 49;
+    private static final int NUMBER_BUCKETS = 50;
+
+    private class SectionStats {
+        private int mNumberSuggestionsShown;
+        private int mNumberSelectionChanges;
+        private int mNumberSelectionEdits;
+        private int mNumberSelectionAdds;
+        private boolean mIsRequested;
+    }
+
+    private SectionStats[] mSections;
+
+    public PaymentRequestJourneyLogger() {
+        mSections = new SectionStats[SECTION_MAX];
+        for (int i = 0; i < mSections.length; ++i) {
+            mSections[i] = new SectionStats();
+        }
+    }
+
+    /*
+     * Sets the number of suggestions shown for the specified section.
+     *
+     * @param section The section for which to log.
+     * @param number The number of suggestions.
+     */
+    public void setNumberOfSuggestionsShown(int section, int number) {
+        assert section < SECTION_MAX;
+        mSections[section].mNumberSuggestionsShown = number;
+    }
+
+    /*
+     * Increments the number of selection changes for the specified section.
+     *
+     * @param section The section for which to log.
+     */
+    public void incrementSelectionChanges(int section) {
+        assert section < SECTION_MAX;
+        ++mSections[section].mNumberSelectionChanges;

[gone, 2016/10/07 18:54:28]

I'd post-increment just to make it clearer.

[sebsg, 2016/10/07 19:40:32]

Done.

+    }
+
+    /*
+     * Increments the number of selection edits for the specified section.
+     *
+     * @param section The section for which to log.
+     */
+    public void incrementSelectionEdits(int section) {
+        assert section < SECTION_MAX;
+        ++mSections[section].mNumberSelectionEdits;
+    }
+
+    /*
+     * Increments the number of selection adds for the specified section.
+     *
+     * @param section The section for which to log.
+     */
+    public void incrementSelectionAdds(int section) {
+        assert section < SECTION_MAX;
+        ++mSections[section].mNumberSelectionAdds;
+    }
+
+    /*
+     * Records that the section was requested by the merchant so the metrics for it will be logged.
+     *
+     * @param section The section that was requested by the merchant.
+     */
+    public void sectionIsRequested(int section) {
+        assert section < SECTION_MAX;
+        mSections[section].mIsRequested = true;
+    }
+
+    /*
+     * Records the histograms for all the sections that were requested by the merchant. This method
+     * should be called when the payment request has either been completed or aborted.
+     *
+     * @param submissionType A string indicating the way the payment request was concluded.
+     */
+    public void recordJourneyStatsHistograms(String submissionType) {
+        for (int i = 0; i < mSections.length; ++i) {
+            String nameSuffix = "";
+            switch (i) {
+                case SECTION_SHIPPING_ADDRESS:
+                    nameSuffix = "ShippingAddress." + submissionType;
+                    break;
+                case SECTION_CONTACT_INFO:
+                    nameSuffix = "ContactInfo." + submissionType;
+                    break;
+                case SECTION_CREDIT_CARDS:
+                    nameSuffix = "CreditCards." + submissionType;
+                    break;
+            }
+
+            assert !nameSuffix.isEmpty();
+
+            // Only log the metrics for a section if it was requested by the merchant.
+            if (mSections[i].mIsRequested) {
+                RecordHistogram.recordCustomCountHistogram(
+                        "PaymentRequest.NumberOfSelectionAdds." + nameSuffix,
+                        Math.min(mSections[i].mNumberSelectionAdds, MAX_EXPECTED_SAMPLE),
+                        MIN_EXPECTED_SAMPLE, MAX_EXPECTED_SAMPLE, NUMBER_BUCKETS);
+                RecordHistogram.recordCustomCountHistogram(
+                        "PaymentRequest.NumberOfSelectionChanges." + nameSuffix,
+                        Math.min(mSections[i].mNumberSelectionChanges, MAX_EXPECTED_SAMPLE),
+                        MIN_EXPECTED_SAMPLE, MAX_EXPECTED_SAMPLE, NUMBER_BUCKETS);
+                RecordHistogram.recordCustomCountHistogram(
+                        "PaymentRequest.NumberOfSelectionEdits." + nameSuffix,
+                        Math.min(mSections[i].mNumberSelectionEdits, MAX_EXPECTED_SAMPLE),
+                        MIN_EXPECTED_SAMPLE, MAX_EXPECTED_SAMPLE, NUMBER_BUCKETS);
+                RecordHistogram.recordCustomCountHistogram(
+                        "PaymentRequest.NumberOfSuggestionsShown." + nameSuffix,
+                        Math.min(mSections[i].mNumberSuggestionsShown, MAX_EXPECTED_SAMPLE),
+                        MIN_EXPECTED_SAMPLE, MAX_EXPECTED_SAMPLE, NUMBER_BUCKETS);
+            }
+        }
+    }
+}