Grant origins engagement for having interactions on their notifications.

chrome/browser/engagement/site_engagement_service.h

Index: chrome/browser/engagement/site_engagement_service.h
diff --git a/chrome/browser/engagement/site_engagement_service.h b/chrome/browser/engagement/site_engagement_service.h
index c97eb4abfa7bfa1aaf3887eb7886d66ced363286..93792b64b0a839cc00127362db866a9327f2aad6 100644
--- a/chrome/browser/engagement/site_engagement_service.h
+++ b/chrome/browser/engagement/site_engagement_service.h
@@ -137,6 +137,8 @@ class SiteEngagementService : public KeyedService,
   double GetTotalEngagementPoints() const override;
 
  private:
+  // TODO(dominickn): remove this friend when we have notification observers.
+  friend class PlatformNotificationServiceImpl;
   friend class SiteEngagementObserver;
   friend class SiteEngagementServiceAndroid;
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, CheckHistograms);
@@ -151,6 +153,8 @@ class SiteEngagementService : public KeyedService,
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, GetMedianEngagement);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, GetTotalNavigationPoints);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, GetTotalUserInputPoints);
+  FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest,
+                           GetTotalNotificationPoints);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, RestrictedToHTTPAndHTTPS);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, LastShortcutLaunch);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, NotificationPermission);
@@ -231,6 +235,9 @@ class SiteEngagementService : public KeyedService,
   void HandleUserInput(content::WebContents* web_contents,
                        SiteEngagementMetrics::EngagementType type);
 
+  // Update the engagement score of |url| for a notification interaction.
+  void HandleNotificationInteraction(const GURL& url);
+
   // Called if |url| changes to |level| engagement, and informs every Helper of
   // the change.
   void SendLevelChangeToHelpers(const GURL& url,