Add a SiteEngagementEvictionPolicy.

storage/browser/quota/quota_manager.h

Index: storage/browser/quota/quota_manager.h
diff --git a/storage/browser/quota/quota_manager.h b/storage/browser/quota/quota_manager.h
index 07106dfe5fb86d299a4c84473182a0490f536f31..1987d6d456205d06d97d3c6a98547c35a250c327 100644
--- a/storage/browser/quota/quota_manager.h
+++ b/storage/browser/quota/quota_manager.h
@@ -69,20 +69,35 @@ struct STORAGE_EXPORT UsageAndQuota {
                 int64 available_disk_space);
 };
 
+// TODO(calamity): Use this in the temporary storage eviction path.
+// An interface for deciding which origin's temporary storage should be evicted
+// when the quota is exceeded.
+class STORAGE_EXPORT QuotaEvictionPolicy {
+ public:
+  // Returns the next origin to evict.  It might return an empty GURL when there
+  // are no evictable origins.
+  virtual void GetEvictionOrigin(
+      const scoped_refptr<SpecialStoragePolicy>& special_storage_policy,
+      const std::map<GURL, int64>& usage_map,
+      int64 global_quota,
+      const GetOriginCallback& callback) = 0;
+
+ protected:
+  ~QuotaEvictionPolicy() {}

[michaeln, 2015/08/26 23:32:37]

Should this dtor be virtual and/or public?

What's the intent of the protected non-virtual destructor? The derived class has
a public virtual dtor. The mix of those is a little odd.

This CL doesn't yet establish ownership of eviction policy objects or how the
quota system gets a ptr to the derived instance. It might make sense for the QM
to get an own ptr to an evictionhandler in its constructor? Did you have
anything in particular in mind.

[calamity, 2015/08/27 05:05:01]

Oops. Yes, this destructor doesn't need to be defined just yet. I think I needed
it for refptr stuff which isn't in this patch? Removing.

I had the full hook-up sorted in another patch which I'm updating and will
upload soon.

+};
+
 // An interface called by QuotaTemporaryStorageEvictor.
 class STORAGE_EXPORT QuotaEvictionHandler {
  public:
-  typedef base::Callback<void(const GURL&)> GetLRUOriginCallback;
   typedef StatusCallback EvictOriginDataCallback;
   typedef base::Callback<void(QuotaStatusCode status,
                               const UsageAndQuota& usage_and_quota)>
       UsageAndQuotaCallback;
 
-  // Returns the least recently used origin.  It might return empty
-  // GURL when there are no evictable origins.
-  virtual void GetLRUOrigin(
-      StorageType type,
-      const GetLRUOriginCallback& callback) = 0;
+  // Returns next origin to evict.  It might return an empty GURL when there are
+  // no evictable origins.
+  virtual void GetEvictionOrigin(StorageType type,
+                                 const GetOriginCallback& callback) = 0;
 
   virtual void EvictOriginData(
       const GURL& origin,
@@ -362,14 +377,16 @@ class STORAGE_EXPORT QuotaManager
                                                int64 unlimited_usage);
 
   // QuotaEvictionHandler.
-  void GetLRUOrigin(StorageType type,
-                    const GetLRUOriginCallback& callback) override;
+  void GetEvictionOrigin(StorageType type,
+                         const GetOriginCallback& callback) override;
   void EvictOriginData(const GURL& origin,
                        StorageType type,
                        const EvictOriginDataCallback& callback) override;
   void GetUsageAndQuotaForEviction(
       const UsageAndQuotaCallback& callback) override;
 
+  void GetLRUOrigin(StorageType type, const GetOriginCallback& callback);
+
   void DidSetTemporaryGlobalOverrideQuota(const QuotaCallback& callback,
                                           const int64* new_quota,
                                           bool success);
@@ -408,7 +425,7 @@ class STORAGE_EXPORT QuotaManager
   scoped_refptr<base::SequencedTaskRunner> db_thread_;
   mutable scoped_ptr<QuotaDatabase> database_;
 
-  GetLRUOriginCallback lru_origin_callback_;
+  GetOriginCallback lru_origin_callback_;
   std::set<GURL> access_notified_origins_;
 
   QuotaClientList clients_;