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

components/ntp_snippets/content_suggestions_metrics.cc

 // 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.
 
 #include "components/ntp_snippets/content_suggestions_metrics.h"
 
 #include <cmath>
 #include <string>
 #include <type_traits>
 
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
 #include "base/strings/stringprintf.h"
 
 namespace ntp_snippets {
 namespace metrics {
 
 namespace {
 
 const int kMaxSuggestionsPerCategory = 10;
 const int kMaxSuggestionsTotal = 50;
 const int kMaxCategories = 10;
 
 const char kHistogramCountOnNtpOpened[] =
     "NewTabPage.ContentSuggestions.CountOnNtpOpened";
+const char kHistogramSectionCountOnNtpOpened[] =
+    "NewTabPage.ContentSuggestions.SectionCountOnNtpOpened";
 const char kHistogramShown[] = "NewTabPage.ContentSuggestions.Shown";
 const char kHistogramShownAge[] = "NewTabPage.ContentSuggestions.ShownAge";
 const char kHistogramShownScore[] =
     "NewTabPage.ContentSuggestions.ShownScoreNormalized";
 const char kHistogramOpened[] = "NewTabPage.ContentSuggestions.Opened";
 const char kHistogramOpenedAge[] = "NewTabPage.ContentSuggestions.OpenedAge";
 const char kHistogramOpenedCategoryIndex[] =
     "NewTabPage.ContentSuggestions.OpenedCategoryIndex";
 const char kHistogramOpenedScore[] =
     "NewTabPage.ContentSuggestions.OpenedScoreNormalized";
@@ skipping 167 matching lines @@
   UMA_HISTOGRAM_EXACT_LINEAR(kHistogramArticlesUsageTimeLocal, bucket,
                              kNumBuckets);
 
   base::RecordAction(
       base::UserMetricsAction("NewTabPage_ContentSuggestions_ArticlesUsage"));
 }
 
 }  // namespace
 
 void OnPageShown(
-    const std::vector<std::pair<Category, int>>& suggestions_per_category) {
+    const std::vector<std::pair<Category, int>>& suggestions_per_category,
+    int visible_categories_count) {
   int suggestions_total = 0;
   for (const std::pair<Category, int>& item : suggestions_per_category) {
     LogCategoryHistogramPosition(kHistogramCountOnNtpOpened, item.first,
                                  item.second, kMaxSuggestionsPerCategory);
     suggestions_total += item.second;
   }
   UMA_HISTOGRAM_EXACT_LINEAR(kHistogramCountOnNtpOpened, suggestions_total,
                              kMaxSuggestionsTotal);
+  UMA_HISTOGRAM_EXACT_LINEAR(kHistogramSectionCountOnNtpOpened,
+                             visible_categories_count, kMaxCategories);
 }
 
 void OnSuggestionShown(int global_position,
                        Category category,
                        int position_in_category,
                        base::Time publish_date,
                        float score,
                        base::Time fetch_date) {
   UMA_HISTOGRAM_EXACT_LINEAR(kHistogramShown, global_position,
                              kMaxSuggestionsTotal);
@@ skipping 141 matching lines @@
 void RecordCategoryDismissed() {
   base::RecordAction(base::UserMetricsAction("Suggestions.Category.Dismissed"));
 }
 
 void RecordFetchAction() {
   base::RecordAction(base::UserMetricsAction("Suggestions.Category.Fetch"));
 }
 
 }  // namespace metrics
 }  // namespace ntp_snippets