[Media Engagment] Add UKM metrics for playback types

Add two UKM fields to Media.Engagement.SessionFinished to
track the total playbacks from audio contexts and media
elements.

BUG=887619

Change-Id: Icb1ed1300114b09737bab2393b5c3d40e870fc5f
Reviewed-on: https://chromium-review.googlesource.com/c/1236924Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#597149}

chrome/browser/media/media_engagement_session.cc

@@ -166,6 +166,8 @@ void MediaEngagementSession::RecordUkmMetrics() {
   MediaEngagementScore score =
       service_->CreateEngagementScore(origin_.GetURL());
   ukm::builders::Media_Engagement_SessionFinished(ukm_source_id_)
+      .SetPlaybacks_AudioContextTotal(score.audio_context_playbacks())
+      .SetPlaybacks_MediaElementTotal(score.media_element_playbacks())
       .SetPlaybacks_Total(score.media_playbacks())
       .SetVisits_Total(score.visits())
       .SetEngagement_Score(round(score.actual_score() * 100))

chrome/browser/media/media_engagement_session_unittest.cc

@@ -707,6 +707,10 @@ TEST_F(MediaEngagementSessionTest, RecordUkmMetrics) {
 
     auto* ukm_entry = ukm_entries[0];
     test_ukm_recorder().ExpectEntrySourceHasUrl(ukm_entry, origin().GetURL());
+    EXPECT_EQ(0, *test_ukm_recorder().GetEntryMetric(
+                     ukm_entry, Entry::kPlaybacks_AudioContextTotalName));
+    EXPECT_EQ(1, *test_ukm_recorder().GetEntryMetric(
+                     ukm_entry, Entry::kPlaybacks_MediaElementTotalName));
     EXPECT_EQ(1, *test_ukm_recorder().GetEntryMetric(
                      ukm_entry, Entry::kPlaybacks_TotalName));
     EXPECT_EQ(1, *test_ukm_recorder().GetEntryMetric(ukm_entry,
@@ -733,8 +737,7 @@ TEST_F(MediaEngagementSessionTest, RecordUkmMetrics) {
                      ukm_entry, Entry::kEngagement_IsHigh_ChangedName));
   }
 
-  SetSignificantMediaElementPlaybackRecordedForSession(session.get(), false);
-  session->RecordSignificantMediaElementPlayback();
+  session->RecordSignificantAudioContextPlayback();
   CommitPendingDataForSession(session.get());
 
   RecordUkmMetricsForSession(session.get());
@@ -745,6 +748,10 @@ TEST_F(MediaEngagementSessionTest, RecordUkmMetrics) {
 
     auto* ukm_entry = ukm_entries[1];
     test_ukm_recorder().ExpectEntrySourceHasUrl(ukm_entry, origin().GetURL());
+    EXPECT_EQ(1, *test_ukm_recorder().GetEntryMetric(
+                     ukm_entry, Entry::kPlaybacks_AudioContextTotalName));
+    EXPECT_EQ(1, *test_ukm_recorder().GetEntryMetric(
+                     ukm_entry, Entry::kPlaybacks_MediaElementTotalName));
     EXPECT_EQ(2, *test_ukm_recorder().GetEntryMetric(
                      ukm_entry, Entry::kPlaybacks_TotalName));
     EXPECT_EQ(1, *test_ukm_recorder().GetEntryMetric(ukm_entry,

tools/metrics/ukm/ukm.xml

@@ -1769,6 +1769,12 @@ be describing additional metrics about the same event.
       be zero. This score is taken from MediaEngagementService.
     </summary>
   </metric>
+  <metric name="Playbacks.AudioContextTotal">
+    <summary>
+      The total number of significant media playbacks on this origin that came
+      from WebAudio / AudioContext.
+    </summary>
+  </metric>
   <metric name="Playbacks.Delta">
     <summary>
       The number of significant media playbacks on this origin during this
@@ -1777,6 +1783,12 @@ be describing additional metrics about the same event.
       200x140px, is not muted, is playing, etc.
     </summary>
   </metric>
+  <metric name="Playbacks.MediaElementTotal">
+    <summary>
+      The total number of significant media playbacks on this origin that came
+      from media elements.
+    </summary>
+  </metric>
   <metric name="Playbacks.SecondsSinceLast">
     <summary>
       The number of seconds between significant media playback on the last visit