Clear up session only storage on localstorage shutdown

content/browser/dom_storage/local_storage_context_mojo.h

 // Copyright 2016 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 CONTENT_BROWSER_DOM_STORAGE_LOCAL_STORAGE_CONTEXT_MOJO_H_
 #define CONTENT_BROWSER_DOM_STORAGE_LOCAL_STORAGE_CONTEXT_MOJO_H_
 
 #include <memory>
 
 #include "base/files/file_path.h"
 #include "content/common/content_export.h"
 #include "content/common/leveldb_wrapper.mojom.h"
+#include "content/public/browser/browser_thread.h"
 #include "services/file/public/interfaces/file_system.mojom.h"
 #include "url/origin.h"
 
 namespace service_manager {
 class Connector;
 }
 
+namespace storage {
+class SpecialStoragePolicy;
+}
+
 namespace content {
 
 class DOMStorageTaskRunner;
 class LevelDBWrapperImpl;
 struct LocalStorageUsageInfo;
 
 // Used for mojo-based LocalStorage implementation (behind --mojo-local-storage
 // for now).
+// Created on the UI thread, but all further methods are called on the IO
+// thread. Furthermore since destruction of this class can involve asynchronous
+// steps, it can only be deleted by calling ShutdownAndDelete (on the IO
+// thread),
 class CONTENT_EXPORT LocalStorageContextMojo {
  public:
   using GetStorageUsageCallback =
       base::OnceCallback<void(std::vector<LocalStorageUsageInfo>)>;
 
-  LocalStorageContextMojo(service_manager::Connector* connector,
-                          scoped_refptr<DOMStorageTaskRunner> task_runner,
-                          const base::FilePath& old_localstorage_path,
-                          const base::FilePath& subdirectory);
-  ~LocalStorageContextMojo();
+  LocalStorageContextMojo(
+      service_manager::Connector* connector,
+      scoped_refptr<DOMStorageTaskRunner> task_runner,
+      const base::FilePath& old_localstorage_path,
+      const base::FilePath& subdirectory,
+      scoped_refptr<storage::SpecialStoragePolicy> special_storage_policy);
 
   void OpenLocalStorage(const url::Origin& origin,
                         mojom::LevelDBWrapperRequest request);
   void GetStorageUsage(GetStorageUsageCallback callback);
   void DeleteStorage(const url::Origin& origin);
   // Like DeleteStorage(), but also deletes storage for all sub-origins.
   void DeleteStorageForPhysicalOrigin(const url::Origin& origin);
   void Flush();
 
+  // Used by content settings to alter the behavior around
+  // what data to keep and what data to discard at shutdown.
+  // The policy is not so straight forward to describe, see
+  // the implementation for details.
+  void SetForceKeepSessionState() { force_keep_session_state_ = true; }
+
+  // Called when the owning BrowserContext is ending.
+  // Schedules the commit of any unsaved changes and will delete
+  // and keep data on disk per the content settings and special storage
+  // policies.
+  void ShutdownAndDelete();
+
   // Clears any caches, to free up as much memory as possible. Next access to
   // storage for a particular origin will reload the data from the database.
   void PurgeMemory();
 
   leveldb::mojom::LevelDBDatabaseAssociatedRequest DatabaseRequestForTesting();
 
   // Converts a string from the old storage format to the new storage format.
   static std::vector<uint8_t> MigrateString(const base::string16& input);
 
  private:
   friend class MojoDOMStorageBrowserTest;
 
   class LevelDBWrapperHolder;
 
+  ~LocalStorageContextMojo();
+
   // Runs |callback| immediately if already connected to a database, otherwise
   // delays running |callback| untill after a connection has been established.
   // Initiates connecting to the database if no connection is in progres yet.
   void RunWhenConnected(base::OnceClosure callback);
 
   // Part of our asynchronous directory opening called from RunWhenConnected().
   void InitiateConnection(bool in_memory_only = false);
   void OnDirectoryOpened(filesystem::mojom::FileError err);
   void OnDatabaseOpened(bool in_memory, leveldb::mojom::DatabaseError status);
   void OnGotDatabaseVersion(leveldb::mojom::DatabaseError status,
@@ skipping 13 matching lines @@
   // directly from that function, or through |on_database_open_callbacks_|.
   void RetrieveStorageUsage(GetStorageUsageCallback callback);
   void OnGotMetaData(GetStorageUsageCallback callback,
                      leveldb::mojom::DatabaseError status,
                      std::vector<leveldb::mojom::KeyValuePtr> data);
 
   void OnGotStorageUsageForDeletePhysicalOrigin(
       const url::Origin& origin,
       std::vector<LocalStorageUsageInfo> usage);
 
-  service_manager::Connector* const connector_;
+  void OnGotStorageUsageForShutdown(std::vector<LocalStorageUsageInfo> usage);
+  void OnShutdownComplete(leveldb::mojom::DatabaseError error);
+
+  std::unique_ptr<service_manager::Connector> connector_;
   const base::FilePath subdirectory_;
 
   enum ConnectionState {
     NO_CONNECTION,
     CONNECTION_IN_PROGRESS,
-    CONNECTION_FINISHED
+    CONNECTION_FINISHED,
+    CONNECTION_SHUTDOWN
   } connection_state_ = NO_CONNECTION;
   bool database_initialized_ = false;
 
+  bool force_keep_session_state_ = false;
+  scoped_refptr<storage::SpecialStoragePolicy> special_storage_policy_;
+
   file::mojom::FileSystemPtr file_system_;
   filesystem::mojom::DirectoryPtr directory_;
 
   leveldb::mojom::LevelDBServicePtr leveldb_service_;
   leveldb::mojom::LevelDBDatabaseAssociatedPtr database_;
   bool tried_to_recreate_ = false;
 
   std::vector<base::OnceClosure> on_database_opened_callbacks_;
 
   // Maps between an origin and its prefixed LevelDB view.
   std::map<url::Origin, std::unique_ptr<LevelDBWrapperHolder>>
       level_db_wrappers_;
 
   // Used to access old data for migration.
   scoped_refptr<DOMStorageTaskRunner> task_runner_;
   base::FilePath old_localstorage_path_;
 
   base::WeakPtrFactory<LocalStorageContextMojo> weak_ptr_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOM_STORAGE_LOCAL_STORAGE_CONTEXT_MOJO_H_