Make Site Engagement behave for adding 0 points.

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 cae312414d83cace067cee9ebd90bb38d3a5f518..2dd143d4709fde45d45e1906313381db9fc47933 100644
--- a/chrome/browser/engagement/site_engagement_service.cc
+++ b/chrome/browser/engagement/site_engagement_service.cc
@@ -265,6 +265,9 @@ SiteEngagementService::SiteEngagementService(Profile* profile,
 }
 
 void SiteEngagementService::AddPoints(const GURL& url, double points) {
+  if (points == 0)
+    return;
+
   // Trigger a cleanup and date adjustment if it has been a substantial length
   // of time since *any* engagement was recorded by the service. This will
   // ensure that we do not decay scores when the user did not use the browser.