Add a SiteEngagementEvictionPolicy.

chrome/browser/engagement/site_engagement_eviction_policy.h

Index: chrome/browser/engagement/site_engagement_eviction_policy.h
diff --git a/chrome/browser/engagement/site_engagement_eviction_policy.h b/chrome/browser/engagement/site_engagement_eviction_policy.h
new file mode 100644
index 0000000000000000000000000000000000000000..bf5c2f1c089a847cad8399dbd62b190f2ecadaae
--- /dev/null
+++ b/chrome/browser/engagement/site_engagement_eviction_policy.h
@@ -0,0 +1,49 @@
+// 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_EVICTION_POLICY_H_
+#define CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_EVICTION_POLICY_H_
+
+#include "storage/browser/quota/quota_manager.h"
+
+class SiteEngagementService;
+
+class SiteEngagementEvictionPolicy
+    : public storage::TemporaryStorageEvictionPolicy {
+ public:
+  explicit SiteEngagementEvictionPolicy(SiteEngagementService* service);
+  virtual ~SiteEngagementEvictionPolicy();
+
+  // Returns the origin from |usage_map| to evict based on usage and site

[raymes, 2015/07/08 04:43:29]

nit: Returns the next origin from |usage_map| to evict

[calamity, 2015/07/10 05:05:05]

Done.

+  // engagement.
+  GURL GetEvictionOriginOnUIThread(const std::map<GURL, int64>& usage_map,
+                                   int64 global_quota);

[raymes, 2015/07/08 04:43:29]

nit: include gurl.h and <map>

[calamity, 2015/07/10 05:05:05]

Done.

+
+  // Overridden from storage::TemporaryStorageEvictionPolicy:
+  void GetEvictionOrigin(
+      const std::map<GURL, int64>& usage_map,
+      int64 global_quota,
+      const storage::GetEvictionOriginCallback& callback) override;
+
+ protected:
+  // Overridden in tests.
+  virtual int GetScore(const GURL& origin);
+  virtual int GetTotalEngagementPoints();
+
+ private:
+  // Gets the quota that an origin deserves based on its site engagement.
+  int64 GetSoftQuotaForOrigin(const GURL& origin,
+                              int64 global_quota,
+                              int total_engagement_points);
+
+  void ReplyWithEvictionOrigin(
+      const storage::GetEvictionOriginCallback& callback,
+      const GURL& origin_to_evict);
+
+  SiteEngagementService* engagement_service_;
+
+  DISALLOW_COPY_AND_ASSIGN(SiteEngagementEvictionPolicy);

[raymes, 2015/07/08 04:43:29]

base/macros.h

[calamity, 2015/07/10 05:05:05]

Done.

+};
+
+#endif  // CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_EVICTION_POLICY_H_