Add UMA metrics to the site engagement service.

chrome/browser/engagement/site_engagement_helper.cc

Index: chrome/browser/engagement/site_engagement_helper.cc
diff --git a/chrome/browser/engagement/site_engagement_helper.cc b/chrome/browser/engagement/site_engagement_helper.cc
index a1f83736780589f22a5bc6319c84fc925f902727..1d52a82c7d112850de13fcd76fa7ccc0bb5bdffd 100644
--- a/chrome/browser/engagement/site_engagement_helper.cc
+++ b/chrome/browser/engagement/site_engagement_helper.cc
@@ -47,7 +47,7 @@ bool SiteEngagementHelper::InputTracker::HandleKeyPressEvent(
   // (e.g. keypress is a key down then key up).
   if (event.type == blink::WebInputEvent::RawKeyDown) {
     PauseTracking(helper_->web_contents()->GetRenderViewHost());
-    helper_->RecordUserInput();
+    helper_->RecordUserInput(SiteEngagementMetrics::ENGAGEMENT_KEYPRESS);
   }
   return false;
 }
@@ -61,7 +61,7 @@ bool SiteEngagementHelper::InputTracker::HandleMouseEvent(
        event.type == blink::WebInputEvent::MouseDown) ||
       event.type == blink::WebInputEvent::MouseWheel) {
     PauseTracking(helper_->web_contents()->GetRenderViewHost());
-    helper_->RecordUserInput();
+    helper_->RecordUserInput(SiteEngagementMetrics::ENGAGEMENT_MOUSE);
   }
   return false;
 }
@@ -125,7 +125,8 @@ SiteEngagementHelper::SiteEngagementHelper(content::WebContents* contents)
       input_tracker_(new InputTracker(this)),
       record_engagement_(false) { }
 
-void SiteEngagementHelper::RecordUserInput() {
+void SiteEngagementHelper::RecordUserInput(
+    SiteEngagementMetrics::EngagementType type) {
   TRACE_EVENT0("SiteEngagement", "RecordUserInput");
   content::WebContents* contents = web_contents();
   if (contents) {
@@ -136,6 +137,7 @@ void SiteEngagementHelper::RecordUserInput() {
 
     // Service is null in incognito.
     if (service) {
+      SiteEngagementMetrics::RecordEngagement(type);
       service->HandleUserInput(contents->GetVisibleURL());
       FOR_EACH_OBSERVER(Observer, observer_list_, OnInputRecorded(this));
     }
@@ -159,8 +161,11 @@ void SiteEngagementHelper::DidNavigateMainFrame(
   SiteEngagementService* service =
       SiteEngagementServiceFactory::GetForProfile(profile);
 
-  if (service)
+  if (service) {
+    SiteEngagementMetrics::RecordEngagement(
+        SiteEngagementMetrics::ENGAGEMENT_NAVIGATION);
     service->HandleNavigation(params.url, params.transition);
+  }
 
   input_tracker_->StartTracking(contents->GetRenderViewHost());
 }