Implement media playing engagement detection for the site engagement service.

chrome/browser/engagement/site_engagement_service.cc

Index: chrome/browser/engagement/site_engagement_service.cc
diff --git a/chrome/browser/engagement/site_engagement_service.cc b/chrome/browser/engagement/site_engagement_service.cc
index d19f37c88d31cb29d3ad95ce11033acaa55f2ba4..ef59192e9e0f4e03088e8639be6b6b4ca2454390 100644
--- a/chrome/browser/engagement/site_engagement_service.cc
+++ b/chrome/browser/engagement/site_engagement_service.cc
@@ -102,6 +102,8 @@ const double SiteEngagementScore::kMaxPoints = 100;
 double SiteEngagementScore::g_max_points_per_day = 5;
 double SiteEngagementScore::g_navigation_points = 0.5;
 double SiteEngagementScore::g_user_input_points = 0.05;
+double SiteEngagementScore::g_visible_media_playing_points = 0.02;
+double SiteEngagementScore::g_hidden_media_playing_points = 0.01;
 int SiteEngagementScore::g_decay_period_in_days = 7;
 double SiteEngagementScore::g_decay_points = 5;
 
@@ -318,6 +320,17 @@ void SiteEngagementService::HandleUserInput(
   RecordMetrics();
 }
 
+void SiteEngagementService::HandleMediaPlaying(const GURL& url,
+                                               bool is_hidden) {
+  SiteEngagementMetrics::RecordEngagement(
+      is_hidden ? SiteEngagementMetrics::ENGAGEMENT_MEDIA_HIDDEN
+                : SiteEngagementMetrics::ENGAGEMENT_MEDIA_VISIBLE);
+  AddPoints(url, is_hidden
+                     ? SiteEngagementScore::g_hidden_media_playing_points
+                     : SiteEngagementScore::g_visible_media_playing_points);
+  RecordMetrics();
+}
+
 double SiteEngagementService::GetScore(const GURL& url) {
   HostContentSettingsMap* settings_map =
     HostContentSettingsMapFactory::GetForProfile(profile_);