📰 Tweak the suggestion ranks for UMA to handle fetchMore

chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsUma.java

Index: chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsUma.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsUma.java b/chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsUma.java
new file mode 100644
index 0000000000000000000000000000000000000000..51456bcf1b0e1d17625d3a59959c1d4292a85b55
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsUma.java
@@ -0,0 +1,48 @@
+// 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.suggestions;
+
+import org.chromium.chrome.browser.ntp.cards.SuggestionsSection;
+import org.chromium.chrome.browser.ntp.snippets.CategoryInt;
+import org.chromium.chrome.browser.ntp.snippets.SnippetArticle;
+
+import java.util.Map;
+import java.util.NoSuchElementException;
+
+/**
+ * Exposes UMA related methods.
+ */
+public class SuggestionsUma {
+    private final Map<Integer, SuggestionsSection> mSections;
+
+    public SuggestionsUma(Map<Integer, SuggestionsSection> sections) {
+        mSections = sections;
+    }
+
+    /** A suggestion's rank is the number of suggestions preceding it in its section. */
+    public int getSuggestionRank(SnippetArticle suggestion) {
+        return mSections.get(suggestion.mCategory).getSuggestionRank(suggestion);
+    }
+
+    /**
+     * A suggestion's global rank is the total number of suggestions preceding it on the current
+     * page.
+     * @param suggestion the suggestion to compute the global rank for.
+     * @param localRank the rank of the suggestion in its section.
+     */
+    public int getSuggestionGlobalRank(SnippetArticle suggestion, int localRank) {
+        return getSectionStartingRank(suggestion.mCategory) + localRank;

[Bernhard Bauer, 2017/01/11 13:53:38]

Would it be simpler to just return an android.util.Pair with the two ranks?

[dgn, 2017/01/12 14:29:58]

Done.

+    }
+
+    /** @return the global rank that the first suggestion of the section would have. */
+    private int getSectionStartingRank(@CategoryInt int category) {
+        int index = 0;
+        for (Map.Entry<Integer, SuggestionsSection> kvPair : mSections.entrySet()) {
+            if (kvPair.getKey() == category) return index;
+            index += kvPair.getValue().getSuggestionsCount();
+        }
+        throw new NoSuchElementException(); // Or return -Inf?
+    }
+}