Plumb site engagement to the renderer process.

chrome/browser/engagement/site_engagement_score.h

Index: chrome/browser/engagement/site_engagement_score.h
diff --git a/chrome/browser/engagement/site_engagement_score.h b/chrome/browser/engagement/site_engagement_score.h
index c2fe659f830b1986829c2810ac358a720fc53b00..bb29a78d6059174828f1f06cdf107be280d9b3d2 100644
--- a/chrome/browser/engagement/site_engagement_score.h
+++ b/chrome/browser/engagement/site_engagement_score.h
@@ -12,6 +12,7 @@
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "base/values.h"
+#include "third_party/WebKit/public/platform/site_engagement.mojom.h"
 #include "url/gurl.h"
 
 namespace base {
@@ -129,6 +130,9 @@ class SiteEngagementScore {
   // Writes the values in this score into |settings_map_|.
   void Commit();
 
+  // Returns the discrete engagement level for this score.
+  blink::mojom::EngagementLevel GetEngagementLevel() const;
+
   // Returns true if the maximum number of points today has been added.
   bool MaxPointsPerDayAdded() const;