[Zine] Add a metric to record number of visible sections on NTP.

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SectionList.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SectionList.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SectionList.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SectionList.java
index 615050325e42acbbe4b86adcc53eb8c40aa041f2..4d8b5c280ece0716ceca72c79238097303e1762e 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SectionList.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SectionList.java
@@ -65,19 +65,22 @@ public class SectionList
         SuggestionsSource suggestionsSource = mUiDelegate.getSuggestionsSource();
         int[] categories = suggestionsSource.getCategories();
         int[] suggestionsPerCategory = new int[categories.length];
+        int visibleCategoriesCount = 0;
         int categoryIndex = 0;
         for (int category : categories) {
             int categoryStatus = suggestionsSource.getCategoryStatus(category);
             int suggestionsCount = 0;
             if (SnippetsBridge.isCategoryEnabled(categoryStatus)) {
                 suggestionsCount = resetSection(category, categoryStatus, alwaysAllowEmptySections);
+                if (mSections.get(category) != null) ++visibleCategoriesCount;
             }
             suggestionsPerCategory[categoryIndex] = suggestionsCount;
             ++categoryIndex;
         }
 
         maybeHideArticlesHeader();
-        mUiDelegate.getEventReporter().onPageShown(categories, suggestionsPerCategory);
+        mUiDelegate.getEventReporter().onPageShown(
+                categories, suggestionsPerCategory, visibleCategoriesCount);
     }
 
     /**