Desktop NTP: Add a UMA metric NewTabPage.TilesReceivedTime

chrome/browser/ui/webui/ntp/ntp_user_data_logger_unittest.cc

Index: chrome/browser/ui/webui/ntp/ntp_user_data_logger_unittest.cc
diff --git a/chrome/browser/ui/webui/ntp/ntp_user_data_logger_unittest.cc b/chrome/browser/ui/webui/ntp/ntp_user_data_logger_unittest.cc
index 46a3a1bce66dd3c08e24cc4c916b9a441c0c9c72..e0876e0eeafc61536d7052e5f8494231b2bd06cc 100644
--- a/chrome/browser/ui/webui/ntp/ntp_user_data_logger_unittest.cc
+++ b/chrome/browser/ui/webui/ntp/ntp_user_data_logger_unittest.cc
@@ -19,6 +19,7 @@ using base::Bucket;
 using ntp_tiles::NTPTileSource;
 using testing::ElementsAre;
 using testing::IsEmpty;
+using testing::SizeIs;
 
 namespace {
 
@@ -211,3 +212,100 @@ TEST(NTPUserDataLoggerTest, TestLogMostVisitedNavigation) {
       histogram_tester.GetAllSamples("NewTabPage.MostVisited.client"),
       ElementsAre(Bucket(1, 1), Bucket(2, 1), Bucket(3, 2)));
 }
+
+TEST(NTPUserDataLoggerTest, TestLoadTime) {
+  base::StatisticsRecorder::Initialize();
+
+  base::HistogramTester histogram_tester;
+
+  TestNTPUserDataLogger logger;
+  logger.ntp_url_ = GURL("chrome://newtab/");
+
+  base::TimeDelta delta_tiles_received = base::TimeDelta::FromMilliseconds(10);
+  base::TimeDelta delta_tiles_loaded = base::TimeDelta::FromMilliseconds(100);
+
+  // Send the ALL_TILES_RECEIVED event.
+  logger.LogEvent(NTP_ALL_TILES_RECEIVED, delta_tiles_received);
+
+  // The actual histograms are emitted only after the ALL_TILES_LOADED event, so
+  // at this point everything should still be empty.

[sfiera, 2017/02/16 14:35:33]

Is this something we actually care about testing? I would be totally OK with it
if TilesReceivedTime were recorded already at this point.

[Marc Treib, 2017/02/16 15:13:09]

Good point. Removed.

+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.TilesReceivedTime"),
+              IsEmpty());
+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.LoadTime"), IsEmpty());
+
+  // Log a TOP_SITES impression (for the .MostVisited vs .MostLikely split in
+  // the LoadTime histogram).
+  logger.LogMostVisitedImpression(0, NTPTileSource::TOP_SITES);
+
+  // Send the ALL_TILES_LOADED event, this should trigger emitting histograms.
+  logger.LogEvent(NTP_ALL_TILES_LOADED, delta_tiles_loaded);
+
+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.TilesReceivedTime"),
+              SizeIs(1));
+  EXPECT_THAT(histogram_tester.GetAllSamples(
+                  "NewTabPage.TilesReceivedTime.MostVisited"),
+              SizeIs(1));
+  EXPECT_THAT(
+      histogram_tester.GetAllSamples("NewTabPage.TilesReceivedTime.MostLikely"),
+      IsEmpty());
+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.LoadTime"), SizeIs(1));
+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.LoadTime.MostVisited"),
+              SizeIs(1));
+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.LoadTime.MostLikely"),
+              IsEmpty());
+
+  histogram_tester.ExpectTimeBucketCount("NewTabPage.TilesReceivedTime",
+                                         delta_tiles_received, 1);
+  histogram_tester.ExpectTimeBucketCount(
+      "NewTabPage.TilesReceivedTime.MostVisited", delta_tiles_received, 1);
+  histogram_tester.ExpectTimeBucketCount("NewTabPage.LoadTime",
+                                         delta_tiles_loaded, 1);
+  histogram_tester.ExpectTimeBucketCount("NewTabPage.LoadTime.MostVisited",
+                                         delta_tiles_loaded, 1);
+
+  // We should not log again for the same NTP.
+  logger.LogEvent(NTP_ALL_TILES_RECEIVED, delta_tiles_received);
+  logger.LogEvent(NTP_ALL_TILES_LOADED, delta_tiles_loaded);
+  histogram_tester.ExpectTimeBucketCount("NewTabPage.TilesReceivedTime",
+                                         delta_tiles_received, 1);
+  histogram_tester.ExpectTimeBucketCount("NewTabPage.LoadTime",
+                                         delta_tiles_loaded, 1);
+
+  // After navigating away from the NTP and back, we record again.
+  logger.NavigatedFromURLToURL(GURL("chrome://newtab/"),
+                               GURL("http://chromium.org"));
+  logger.NavigatedFromURLToURL(GURL("http://chromium.org"),
+                               GURL("chrome://newtab/"));
+
+  // This time, log a SUGGESTIONS_SERVICE impression, so the load time will end
+  // up in .MostLikely.
+  logger.LogMostVisitedImpression(0, NTPTileSource::SUGGESTIONS_SERVICE);
+
+  base::TimeDelta delta_tiles_received2 = base::TimeDelta::FromMilliseconds(50);
+  base::TimeDelta delta_tiles_loaded2 = base::TimeDelta::FromMilliseconds(500);
+  logger.LogEvent(NTP_ALL_TILES_RECEIVED, delta_tiles_received2);
+  logger.LogEvent(NTP_ALL_TILES_LOADED, delta_tiles_loaded2);
+
+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.TilesReceivedTime"),
+              SizeIs(2));
+  EXPECT_THAT(histogram_tester.GetAllSamples(
+                  "NewTabPage.TilesReceivedTime.MostVisited"),
+              SizeIs(1));
+  EXPECT_THAT(
+      histogram_tester.GetAllSamples("NewTabPage.TilesReceivedTime.MostLikely"),
+      SizeIs(1));
+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.LoadTime"), SizeIs(2));
+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.LoadTime.MostVisited"),
+              SizeIs(1));
+  EXPECT_THAT(histogram_tester.GetAllSamples("NewTabPage.LoadTime.MostLikely"),
+              SizeIs(1));
+
+  histogram_tester.ExpectTimeBucketCount("NewTabPage.TilesReceivedTime",
+                                         delta_tiles_received2, 1);
+  histogram_tester.ExpectTimeBucketCount(
+      "NewTabPage.TilesReceivedTime.MostLikely", delta_tiles_received2, 1);
+  histogram_tester.ExpectTimeBucketCount("NewTabPage.LoadTime",
+                                         delta_tiles_loaded2, 1);
+  histogram_tester.ExpectTimeBucketCount("NewTabPage.LoadTime.MostLikely",
+                                         delta_tiles_loaded2, 1);
+}