Implement a basic Site Engagement Score service.

chrome/browser/engagement/site_engagement_service.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/engagement/site_engagement_service.h"
+
+#include <algorithm>
+
+#include "base/command_line.h"
+#include "chrome/browser/engagement/site_engagement_helper.h"
+#include "chrome/browser/engagement/site_engagement_service_factory.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/common/chrome_switches.h"
+#include "url/gurl.h"
+
+// static
+SiteEngagementService* SiteEngagementService::Get(Profile* profile) {
+  return SiteEngagementServiceFactory::GetForProfile(profile);
+}
+
+// static
+bool SiteEngagementService::IsEnabled() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableSiteEngagementService);
+}
+
+SiteEngagementService::SiteEngagementService(Profile* profile)
+    : profile_(profile) {
+}
+
+SiteEngagementService::~SiteEngagementService() {
+}
+
+void SiteEngagementService::HandleNavigation(const GURL& url) {
+  GURL origin = url.GetOrigin();
+  scores_[origin] = scores_[origin] + 1;
+  url.GetOrigin();

[raymes, 2015/04/16 01:13:55]

nit: remove this line

[benwells, 2015/04/16 05:15:27]

Done.

+}
+
+int SiteEngagementService::GetScore(const GURL& url) {
+  return scores_[url.GetOrigin()];
+}
+