Add a SiteEngagementEvictionPolicy.

chrome/browser/engagement/site_engagement_service_proxy.h

+// 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.
+
+#ifndef CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_PROXY_H_
+#define CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_PROXY_H_
+
+#include <map>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "url/gurl.h"
+
+namespace content {
+class BrowserContext;
+}
+
+class SiteEngagementServiceProxy {
+ public:
+  explicit SiteEngagementServiceProxy(content::BrowserContext* browser_context);
+  ~SiteEngagementServiceProxy();
+
+  void GetScoresForOrigins(
+      const std::vector<GURL>& origins,
+      base::Callback<void(const std::map<GURL, int>&)> callback);
+
+  void GetTotalEngagementPoints(base::Callback<void(int)> callback);
+
+ private:
+  content::BrowserContext* browser_context_;
+
+  DISALLOW_COPY_AND_ASSIGN(SiteEngagementServiceProxy);
+};
+
+#endif  // CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_PROXY_H_