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..673dd4aa926c6526e20886cbb29ec526a7d64f67
--- /dev/null
+++ b/chrome/browser/engagement/site_engagement_eviction_policy.h
@@ -0,0 +1,75 @@
+// 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 <map>
+
+#include "base/macros.h"
+#include "chrome/browser/engagement/site_engagement_service_proxy.h"
+#include "storage/browser/quota/quota_manager.h"
+#include "url/gurl.h"
+
+namespace content {
+class BrowserContext;
+}
+
+class SiteEngagementEvictionPolicy
+    : public storage::TemporaryStorageEvictionPolicy {
+ public:
+  // A task that calculates the next origin to evict based on usage and site
+  // engagement.
+  class GetEvictionOriginTask {

[raymes, 2015/07/15 07:55:47]

This should be a private class, right?

[calamity, 2015/07/20 06:39:44]

Hmm. I originally did have it as an anonymous class in the .cc but exposed it
here for testing. I guess I can make it private and friend the test.

+   public:
+    GetEvictionOriginTask(
+        content::BrowserContext* browser_context,
+        const std::map<GURL, int64>& usage_map,
+        int64 global_quota,
+        const storage::GetEvictionOriginCallback& result_callback);
+
+    void Start();
+
+   private:
+    void OnDidGetScoresForOrigin(const std::map<GURL, int>& score_map);
+    void OnDidGetTotalEngagementPoints(int total_engagement_points);
+
+    void CalculateEvictionOriginAndReply();
+
+    // Gets the quota that an origin deserves based on its site engagement.
+    int64 GetSoftQuotaForOrigin(const GURL& origin);
+    ~GetEvictionOriginTask();
+
+    std::map<GURL, int64> usage_map_;
+    int64 global_quota_;
+
+    std::map<GURL, int> score_map_;
+    int total_engagement_points_;
+
+    // The callback that each task runs as it completes.
+    base::Closure per_task_callback_;
+
+    // The callback to run with the next eviction origin.
+    storage::GetEvictionOriginCallback result_callback_;
+
+    SiteEngagementServiceProxy proxy_;
+  };
+
+  explicit SiteEngagementEvictionPolicy(
+      content::BrowserContext* browser_context);
+  virtual ~SiteEngagementEvictionPolicy();
+
+  // Overridden from storage::TemporaryStorageEvictionPolicy:
+  void GetEvictionOrigin(
+      const std::map<GURL, int64>& usage_map,
+      int64 global_quota,
+      const storage::GetEvictionOriginCallback& callback) override;
+
+ private:
+  content::BrowserContext* browser_context_;
+
+  DISALLOW_COPY_AND_ASSIGN(SiteEngagementEvictionPolicy);
+};
+
+#endif  // CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_EVICTION_POLICY_H_