Add metrics for trending tiles

BUG=1159109

Change-Id: Iba334d54feb3574a5c81d18c3f1d042d2c7803de
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2593742
Commit-Queue: Min Qin <qinmin@chromium.org>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#837788}

components/query_tiles/internal/stats.cc

@@ -29,6 +29,9 @@ const char kFetcherStartHourHistogram[] = "Search.QueryTiles.Fetcher.Start";
 const char kPrunedGroupReasonHistogram[] =
     "Search.QueryTiles.Group.PruneReason";
 
+const char kTrendingTileEventHistogram[] =
+    "Search.QueryTiles.TrendingTileEvent";
+
 void RecordImageLoading(ImagePreloadingEvent event) {
   base::UmaHistogramEnumeration(kImagePreloadingHistogram, event);
 }
@@ -61,5 +64,9 @@ void RecordGroupPruned(PrunedGroupReason reason) {
   base::UmaHistogramEnumeration(kPrunedGroupReasonHistogram, reason);
 }
 
+void RecordTrendingTileEvent(TrendingTileEvent event) {
+  base::UmaHistogramEnumeration(kTrendingTileEventHistogram, event);
+}
+
 }  // namespace stats
 }  // namespace query_tiles

components/query_tiles/internal/stats.h

@@ -26,6 +26,8 @@ extern const char kFetcherStartHourHistogram[];
 
 extern const char kPrunedGroupReasonHistogram[];
 
+extern const char kTrendingTileEventHistogram[];
+
 // Event to track image loading metrics.
 enum class ImagePreloadingEvent {
   // Start to fetch image in full browser mode.
@@ -51,6 +53,19 @@ enum class PrunedGroupReason {
   kMaxValue = kInvalidLocale,
 };
 
+// Event to track trending tile metrics.
+// These values are persisted to logs. Entries should not be renumbered and
+// numeric values should never be reused.
+enum class TrendingTileEvent {
+  // A trending tile is shown.
+  kShown = 0,
+  // A trending tile is removed.
+  kRemoved = 1,
+  // A trending tile is clicked.
+  kClicked = 2,
+  kMaxValue = kClicked,
+};
+
 // Records an image preloading event.
 void RecordImageLoading(ImagePreloadingEvent event);
 
@@ -76,6 +91,9 @@ void RecordExplodeOnFetchStarted(int explode);
 // Records the reason to cause TileManager to prune the group.
 void RecordGroupPruned(PrunedGroupReason reason);
 
+// Records the event for trending tile.
+void RecordTrendingTileEvent(TrendingTileEvent event);
+
 }  // namespace stats
 }  // namespace query_tiles
 

components/query_tiles/internal/stats_unittest.cc

@@ -60,5 +60,14 @@ TEST(QueryTilesStatsTest, RecordGroupPruned) {
   tester.ExpectBucketCount(stats::kPrunedGroupReasonHistogram, 1, 1);
 }
 
+TEST(QueryTilesStatsTest, RecordTrendingTileEvent) {
+  base::HistogramTester tester;
+  stats::RecordTrendingTileEvent(stats::TrendingTileEvent::kRemoved);
+  stats::RecordTrendingTileEvent(stats::TrendingTileEvent::kClicked);
+  tester.ExpectBucketCount(stats::kTrendingTileEventHistogram, 0, 0);
+  tester.ExpectBucketCount(stats::kTrendingTileEventHistogram, 1, 1);
+  tester.ExpectBucketCount(stats::kTrendingTileEventHistogram, 2, 1);
+}
+
 }  // namespace
 }  // namespace query_tiles

components/query_tiles/internal/trending_tile_handler.cc

@@ -4,6 +4,7 @@
 
 #include "components/query_tiles/internal/trending_tile_handler.h"
 
+#include "components/query_tiles/internal/stats.h"
 #include "components/query_tiles/internal/tile_config.h"
 #include "components/query_tiles/internal/tile_utils.h"
 #include "components/query_tiles/switches.h"
@@ -36,6 +37,8 @@ std::vector<Tile> TrendingTileHandler::FilterExtraTrendingTiles(
 
 void TrendingTileHandler::OnTileClicked(const std::string& tile_id) {
   tile_impressions_.erase(tile_id);
+  if (IsTrendingTile(tile_id))
+    stats::RecordTrendingTileEvent(stats::TrendingTileEvent::kClicked);
 }
 
 std::vector<std::string> TrendingTileHandler::GetInactiveTrendingTiles() {
@@ -49,6 +52,7 @@ std::vector<std::string> TrendingTileHandler::GetInactiveTrendingTiles() {
     if (it->second >= TileConfig::GetMaxTrendingTileImpressions()) {
       tile_ids.emplace_back(it->first);
       it = tile_impressions_.erase(it);
+      stats::RecordTrendingTileEvent(stats::TrendingTileEvent::kRemoved);
     } else {
       ++it;
     }
@@ -59,6 +63,7 @@ std::vector<std::string> TrendingTileHandler::GetInactiveTrendingTiles() {
 
 void TrendingTileHandler::RecordImpression(const std::string& tile_id) {
   ++tile_impressions_[tile_id];
+  stats::RecordTrendingTileEvent(stats::TrendingTileEvent::kShown);
 }
 
 }  // namespace query_tiles

tools/metrics/histograms/enums.xml

@@ -74072,6 +74072,12 @@ Full version information for the fingerprint enum values:
   <int value="15" label="Automatic translation, by user preference"/>
 </enum>
 
+<enum name="TrendingTileEvent">
+  <int value="0" label="Tile was shown"/>
+  <int value="1" label="Tile was removed"/>
+  <int value="2" label="Tile was clicked"/>
+</enum>
+
 <enum name="TriggerHelpUIResult">
   <int value="0" label="SUCCESS"/>
   <int value="1" label="FAILURE"/>

tools/metrics/histograms/histograms_xml/search/histograms.xml

@@ -1403,6 +1403,16 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="Search.QueryTiles.TrendingTileEvent" enum="TrendingTileEvent"
+    expires_after="M91">
+  <owner>qinmin@chromium.org</owner>
+  <owner>chrome-upboarding-eng@google.com</owner>
+  <summary>
+    Records events related to trending tiles, including display, removal and
+    click, after the events occur.
+  </summary>
+</histogram>
+
 <histogram name="Search.RelatedSearches.AllUserPermissions"
     enum="ContextualSearchPermissions" expires_after="M91">
   <owner>donnd@chromium.org</owner>