[Media Engagement] Track AudioContext playbacks

Adds AudioContext player tracking to MediaEngagementContentsObserver
with it's own page level timer. On MediaEngagementSession this CL
seperates significant playback into media element playback and
audio context playback. Since we may record a playback we need to
disable committing on significant playback and just record on
destroy or navigate instead.

BUG=878460

Change-Id: Ic66152f8cb5b3a6338804c04de7dd0bf5c1cb154
Reviewed-on: https://chromium-review.googlesource.com/1194992
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587899}

chrome/browser/media/media_engagement_browsertest.cc

@@ -337,7 +337,7 @@ class MediaEngagementPreloadBrowserTest : public InProcessBrowserTest {
 IN_PROC_BROWSER_TEST_F(MediaEngagementBrowserTest, RecordEngagement) {
   LoadTestPageAndWaitForPlayAndAudible("engagement_test.html", false);
   AdvanceMeaningfulPlaybackTime();
-  ExpectScores(1, 1, 0, 0);
+  ExpectScores(0, 0, 0, 0);
   CloseTab();
   ExpectScores(1, 1, 1, 1);
 }

chrome/browser/media/media_engagement_contents_observer.cc

@@ -122,6 +122,8 @@ void MediaEngagementContentsObserver::ClearPlayerStates() {
   playback_timer_.Stop();
   player_states_.clear();
   significant_players_.clear();
+  audio_context_players_.clear();
+  audio_context_timer_.Stop();
 }
 
 void MediaEngagementContentsObserver::RegisterAudiblePlayersWithSession() {
@@ -270,8 +272,21 @@ void MediaEngagementContentsObserver::MediaStoppedPlaying(
   UpdatePlayerTimer(media_player_id);
 }
 
+void MediaEngagementContentsObserver::AudioContextPlaybackStarted(
+    const AudioContextId& audio_context_id) {
+  audio_context_players_.insert(audio_context_id);
+  UpdateAudioContextTimer();
+}
+
+void MediaEngagementContentsObserver::AudioContextPlaybackStopped(
+    const AudioContextId& audio_context_id) {
+  audio_context_players_.erase(audio_context_id);
+  UpdateAudioContextTimer();
+}
+
 void MediaEngagementContentsObserver::DidUpdateAudioMutingState(bool muted) {
   UpdatePageTimer();
+  UpdateAudioContextTimer();
 }
 
 std::vector<MediaEngagementContentsObserver::InsignificantPlaybackReason>
@@ -330,7 +345,23 @@ void MediaEngagementContentsObserver::OnSignificantMediaPlaybackTimeForPlayer(
 void MediaEngagementContentsObserver::OnSignificantMediaPlaybackTimeForPage() {
   DCHECK(session_);
 
-  if (session_->significant_playback_recorded())
+  if (session_->significant_media_element_playback_recorded())
+    return;
+
+  // Do not record significant playback if the tab did not make
+  // a sound recently.
+  auto* audible_helper = RecentlyAudibleHelper::FromWebContents(web_contents());
+  if (!audible_helper->WasRecentlyAudible())
+    return;
+
+  session_->RecordSignificantMediaElementPlayback();
+}
+
+void MediaEngagementContentsObserver::
+    OnSignificantAudioContextPlaybackTimeForPage() {
+  DCHECK(session_);
+
+  if (session_->significant_audio_context_playback_recorded())
     return;
 
   // Do not record significant playback if the tab did not make
@@ -339,7 +370,7 @@ void MediaEngagementContentsObserver::OnSignificantMediaPlaybackTimeForPage() {
   if (!audible_helper->WasRecentlyAudible())
     return;
 
-  session_->RecordSignificantPlayback();
+  session_->RecordSignificantAudioContextPlayback();
 }
 
 void MediaEngagementContentsObserver::RecordInsignificantReasons(
@@ -474,7 +505,7 @@ bool MediaEngagementContentsObserver::AreConditionsMet() const {
 }
 
 void MediaEngagementContentsObserver::UpdatePageTimer() {
-  if (!session_ || session_->significant_playback_recorded())
+  if (!session_ || session_->significant_media_element_playback_recorded())
     return;
 
   if (AreConditionsMet()) {
@@ -497,6 +528,35 @@ void MediaEngagementContentsObserver::UpdatePageTimer() {
   }
 }
 
+bool MediaEngagementContentsObserver::AreAudioContextConditionsMet() const {
+  if (audio_context_players_.empty())
+    return false;
+
+  return !web_contents()->IsAudioMuted();
+}
+
+void MediaEngagementContentsObserver::UpdateAudioContextTimer() {
+  if (!session_ || session_->significant_audio_context_playback_recorded())
+    return;
+
+  if (AreAudioContextConditionsMet()) {
+    if (audio_context_timer_.IsRunning())
+      return;
+
+    if (task_runner_)
+      audio_context_timer_.SetTaskRunner(task_runner_);
+
+    audio_context_timer_.Start(
+        FROM_HERE,
+        MediaEngagementContentsObserver::kSignificantMediaPlaybackTime,
+        base::Bind(&MediaEngagementContentsObserver::
+                       OnSignificantAudioContextPlaybackTimeForPage,
+                   base::Unretained(this)));
+  } else if (audio_context_timer_.IsRunning()) {
+    audio_context_timer_.Stop();
+  }
+}
+
 void MediaEngagementContentsObserver::SetTaskRunnerForTest(
     scoped_refptr<base::SequencedTaskRunner> task_runner) {
   task_runner_ = std::move(task_runner);

chrome/browser/media/media_engagement_contents_observer.h

@@ -39,6 +39,10 @@ class MediaEngagementContentsObserver : public content::WebContentsObserver {
   void DidUpdateAudioMutingState(bool muted) override;
   void MediaMutedStatusChanged(const MediaPlayerId& id, bool muted) override;
   void MediaResized(const gfx::Size& size, const MediaPlayerId& id) override;
+  void AudioContextPlaybackStarted(
+      const AudioContextId& audio_context_id) override;
+  void AudioContextPlaybackStopped(
+      const AudioContextId& audio_context_id) override;
 
   static const gfx::Size kSignificantSize;
   static const char* const kHistogramScoreAtPlaybackName;
@@ -96,9 +100,14 @@ class MediaEngagementContentsObserver : public content::WebContentsObserver {
 
   void OnSignificantMediaPlaybackTimeForPlayer(const MediaPlayerId& id);
   void OnSignificantMediaPlaybackTimeForPage();
+  void OnSignificantAudioContextPlaybackTimeForPage();
+
   void UpdatePlayerTimer(const MediaPlayerId&);
   void UpdatePageTimer();
+  void UpdateAudioContextTimer();
+
   bool AreConditionsMet() const;
+  bool AreAudioContextConditionsMet() const;
 
   void SetTaskRunnerForTest(scoped_refptr<base::SequencedTaskRunner>);
 
@@ -114,6 +123,13 @@ class MediaEngagementContentsObserver : public content::WebContentsObserver {
   // significant playback.
   std::set<MediaPlayerId> significant_players_;
 
+  // Timer that will fire when the playback time of any audio context reaches
+  // the minimum for significant media playback.
+  base::OneShotTimer audio_context_timer_;
+
+  // Set of active audio contexts that can produce a significant playback.
+  std::set<AudioContextId> audio_context_players_;
+
   // Measures playback time for a player.
   class PlaybackTimer {
    public: