ServiceWorker: Migrate the script cache backend from BlockFile to Simple

content/browser/service_worker/service_worker_database.h

Index: content/browser/service_worker/service_worker_database.h
diff --git a/content/browser/service_worker/service_worker_database.h b/content/browser/service_worker/service_worker_database.h
index 13c0ed480a2623772118475ea4c07264a302d825..21da4658f13af0fa74dcb41c2381bbd90e8a5027 100644
--- a/content/browser/service_worker/service_worker_database.h
+++ b/content/browser/service_worker/service_worker_database.h
@@ -92,6 +92,14 @@ class CONTENT_EXPORT ServiceWorkerDatabase {
       int64* next_avail_version_id,
       int64* next_avail_resource_id);
 
+  // Reads the current diskcache version from the database. If the database
+  // hasn't been written anything yet, sets |disk_cache_version| to 0 and
+  // returns OK.
+  Status ReadDiskCacheVersion(int64* disk_cache_version);
+
+  // Writes the current diskcache version into the database.
+  Status WriteDiskCacheVersion(int64 disk_cache_version);
+
   // Reads origins that have one or more than one registration from the
   // database. Returns OK if they are successfully read or not found.
   // Otherwise, returns an error.
@@ -224,6 +232,23 @@ class CONTENT_EXPORT ServiceWorkerDatabase {
   // Returns OK on success. Otherwise deletes nothing and returns an error.
   Status PurgeUncommittedResourceIds(const std::set<int64>& ids);
 
+  // These *PurgeableFile functions are used for tracking purgeable files placed
+  // under the service worker directory (ie. kServiceWorkerDirectory defined in
+  // ServiceWorkerContextCore). The files should be deletable on the diskcache
+  // thread.
+
+  // Reads filenames of purgeable files from the database. Returns OK on success
+  // even if there are no purgeable files in the database.
+  Status GetPurgeableFiles(std::vector<std::string>* filenames);
+
+  // Writes |filename| into the database as a purgeable file. Returns OK on
+  // success.
+  Status WritePurgeableFile(const std::string& filename);
+
+  // Deletes a purgeable file specified by |filename| from the database. Returns
+  // OK on success.
+  Status ClearPurgeableFile(const std::string& filename);
+
   // Deletes all data for |origins|, namely, unique origin, registrations and
   // resource records. Resources are moved to the purgeable list. Returns OK if
   // they are successfully deleted or not found in the database. Otherwise,
@@ -370,6 +395,7 @@ class CONTENT_EXPORT ServiceWorkerDatabase {
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, OpenDatabase);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, OpenDatabase_InMemory);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, DatabaseVersion);
+  FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, DiskCacheVersion);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, GetNextAvailableIds);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest,
                            Registration_UninitializedDatabase);