ServiceWorker: Migrate the script cache backend from BlockFile to Simple

content/browser/service_worker/service_worker_storage.h

Index: content/browser/service_worker/service_worker_storage.h
diff --git a/content/browser/service_worker/service_worker_storage.h b/content/browser/service_worker/service_worker_storage.h
index 1bfa737d83679f42b96dda6b49c652117d56a3c3..66d94081b49b182c94fa1306ae4654adc84961d1 100644
--- a/content/browser/service_worker/service_worker_storage.h
+++ b/content/browser/service_worker/service_worker_storage.h
@@ -18,6 +18,7 @@
 #include "base/memory/weak_ptr.h"
 #include "content/browser/service_worker/service_worker_database.h"
 #include "content/browser/service_worker/service_worker_database_task_manager.h"
+#include "content/browser/service_worker/service_worker_metrics.h"
 #include "content/browser/service_worker/service_worker_version.h"
 #include "content/common/content_export.h"
 #include "content/common/service_worker/service_worker_status_code.h"
@@ -37,6 +38,7 @@ namespace content {
 
 class ServiceWorkerContextCore;
 class ServiceWorkerDiskCache;
+class ServiceWorkerDiskCacheMigrator;
 class ServiceWorkerRegistration;
 class ServiceWorkerResponseMetadataWriter;
 class ServiceWorkerResponseReader;
@@ -212,11 +214,16 @@ class CONTENT_EXPORT ServiceWorkerStorage
   friend class ServiceWorkerResourceStorageTest;
   friend class ServiceWorkerControlleeRequestHandlerTest;
   friend class ServiceWorkerContextRequestHandlerTest;
+  friend class ServiceWorkerDiskCacheMigratorTest;
   friend class ServiceWorkerRequestHandlerTest;
   friend class ServiceWorkerURLRequestJobTest;
   friend class ServiceWorkerVersionBrowserTest;
   friend class ServiceWorkerVersionTest;
   friend class ServiceWorkerWriteToCacheJobTest;
+  FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDiskCacheMigratorTest,
+                           MigrateOnDiskCacheAccess);
+  FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDiskCacheMigratorTest,
+                           NotMigrateOnDatabaseAccess);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDispatcherHostTest,
                            CleanupOnRendererCrash);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerResourceStorageTest,
@@ -255,9 +262,11 @@ class CONTENT_EXPORT ServiceWorkerStorage
   typedef std::vector<ServiceWorkerDatabase::RegistrationData> RegistrationList;
   typedef std::map<int64, scoped_refptr<ServiceWorkerRegistration> >
       RegistrationRefsById;
-  typedef base::Callback<void(
-      InitialData* data,
-      ServiceWorkerDatabase::Status status)> InitializeCallback;
+  typedef base::Callback<void(InitialData* data,
+                              int64 current_disk_cache_version,
+                              const std::vector<std::string>& purgeable_files,
+                              ServiceWorkerDatabase::Status status)>
+      InitializeCallback;
   typedef base::Callback<void(
       const GURL& origin,
       const ServiceWorkerDatabase::RegistrationData& deleted_version_data,
@@ -294,13 +303,18 @@ class CONTENT_EXPORT ServiceWorkerStorage
   base::FilePath GetDatabasePath();
   base::FilePath GetDiskCachePath();
 
-  // Loads the registration data from backend storage. This must be called
-  // before any method that requires registration data.
+  // Returns a path to an old diskcache backed with BlockFile. This is used for
+  // the diskcache migration (see service_worker_disk_cache_migrator.h).
+  // TODO(nhiroki): Remove this after several milestones pass
+  // (http://crbug.com/487482)
+  base::FilePath GetOldDiskCachePath();
+
   bool LazyInitialize(
       const base::Closure& callback);
-  void DidReadInitialData(
-      InitialData* data,
-      ServiceWorkerDatabase::Status status);
+  void DidReadInitialData(InitialData* data,
+                          int64 current_disk_cache_version,
+                          const std::vector<std::string>& purgeable_files,
+                          ServiceWorkerDatabase::Status status);
   void DidFindRegistrationForDocument(
       const GURL& document_url,
       const FindRegistrationCallback& callback,
@@ -358,6 +372,7 @@ class CONTENT_EXPORT ServiceWorkerStorage
       const FindRegistrationCallback& callback,
       const ServiceWorkerDatabase::RegistrationData& data,
       const ResourceList& resources);
+  void DidWriteDatabase(ServiceWorkerDatabase::Status status);
 
   scoped_refptr<ServiceWorkerRegistration> GetOrCreateRegistration(
       const ServiceWorkerDatabase::RegistrationData& data,
@@ -371,6 +386,10 @@ class CONTENT_EXPORT ServiceWorkerStorage
 
   // Lazy disk_cache getter.
   ServiceWorkerDiskCache* disk_cache();
+  void MigrateDiskCache();
+  void DidMigrateDiskCache(ServiceWorkerStatusCode status);
+  void DidPurgeFile(bool deleted);
+  void InitializeDiskCache();
   void OnDiskCacheInitialized(int rv);
 
   void StartPurgingResources(const std::vector<int64>& ids);
@@ -485,7 +504,11 @@ class CONTENT_EXPORT ServiceWorkerStorage
   scoped_refptr<base::SingleThreadTaskRunner> disk_cache_thread_;
   scoped_refptr<storage::QuotaManagerProxy> quota_manager_proxy_;
   scoped_refptr<storage::SpecialStoragePolicy> special_storage_policy_;
+
   scoped_ptr<ServiceWorkerDiskCache> disk_cache_;
+  scoped_ptr<ServiceWorkerDiskCacheMigrator> disk_cache_migrator_;
+  int64 current_disk_cache_version_;
+
   std::deque<int64> purgeable_resource_ids_;
   bool is_purge_pending_;
   bool has_checked_for_stale_resources_;