Restore sessionStorage when chrome restarts.

content/browser/in_process_webkit/dom_storage_context.h

 // Copyright (c) 2011 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_IN_PROCESS_WEBKIT_DOM_STORAGE_CONTEXT_H_
 #define CONTENT_BROWSER_IN_PROCESS_WEBKIT_DOM_STORAGE_CONTEXT_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 49 matching lines @@
   DOMStorageArea* GetStorageArea(int64 id);
 
   // Called on WebKit thread when a session storage namespace can be deleted.
   void DeleteSessionStorageNamespace(int64 namespace_id);
 
   // Get a namespace from an id.  What's returned is owned by this class.  If
   // allocation_allowed is true, then this function will create the storage
   // namespace if it hasn't been already.
   DOMStorageNamespace* GetStorageNamespace(int64 id, bool allocation_allowed);
 
+  // Creates a session storage namespace which is backed up by the existing
+  // |session_storage_directory|.
+  DOMStorageNamespace* RecreateSessionStorageNamespace(
+      int64 id,
+      const FilePath& session_storage_directory);
+
   // Sometimes an event from one DOM storage message filter requires
   // communication to all of them.
   typedef std::set<DOMStorageMessageFilter*> MessageFilterSet;
   void RegisterMessageFilter(DOMStorageMessageFilter* message_filter);
   void UnregisterMessageFilter(DOMStorageMessageFilter* MessageFilter);
   const MessageFilterSet* GetMessageFilterSet() const;
 
   // Tells storage namespaces to purge any memory they do not need.
   virtual void PurgeMemory();
 
   // Delete any local storage files that have been touched since the cutoff
   // date that's supplied. Protected origins, per the SpecialStoragePolicy,
   // are not deleted by this method.
   void DeleteDataModifiedSince(const base::Time& cutoff);
 
   // Deletes a single local storage file.
   void DeleteLocalStorageFile(const FilePath& file_path);
 
   // Deletes the local storage file for the given origin.
   void DeleteLocalStorageForOrigin(const string16& origin_id);
 
   // Deletes all local storage files.
   void DeleteAllLocalStorageFiles();
 
   // The local storage directory.
   static const FilePath::CharType kLocalStorageDirectory[];
 
+  // The session storage directory.
+  static const FilePath::CharType kSessionStorageDirectory[];
+
   // The local storage file extension.
   static const FilePath::CharType kLocalStorageExtension[];
 
   // Get the file name of the local storage file for the given origin.
   FilePath GetLocalStorageFilePath(const string16& origin_id) const;
 
   void set_clear_local_state_on_exit_(bool clear_local_state) {
     clear_local_state_on_exit_ = clear_local_state;
   }
 
   // Disables the exit-time deletion for all data (also session-only data).
   void SaveSessionState() {
     save_session_state_ = true;
   }
 
   void set_data_path_for_testing(const FilePath& data_path) {
     data_path_ = data_path;
   }
 
+  // Deletes the session storages which are not in |needed_session_storages|.
+  void DeleteUnneededSessionStorages(
+      const std::set<std::string>& needed_session_storages);
+
  private:
 
   FRIEND_TEST_ALL_PREFIXES(DOMStorageTest, SessionOnly);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageTest, SaveSessionState);
 
   // Get the local storage instance.  The object is owned by this class.
   DOMStorageNamespace* CreateLocalStorage();
 
   // Get a new session storage namespace.  The object is owned by this class.
   DOMStorageNamespace* CreateSessionStorage(int64 namespace_id);
 
   // Used internally to register storage namespaces we create.
   void RegisterStorageNamespace(DOMStorageNamespace* storage_namespace);
 
   // The WebKit thread half of CloneSessionStorage above.  Static because
   // DOMStorageContext isn't ref counted thus we can't use a runnable method.
   // That said, we know this is safe because this class is destroyed on the
   // WebKit thread, so there's no way it could be destroyed before this is run.
   static void CompleteCloningSessionStorage(DOMStorageContext* context,
-                                            int64 existing_id, int64 clone_id);
+                                            int64 existing_id, int64 clone_id,
+                                            const FilePath& data_path);
 
   // The last used storage_area_id and storage_namespace_id's.  For the storage
   // namespaces, IDs allocated on the UI thread are positive and count up while
   // IDs allocated on the IO thread are negative and count down.  This allows us
   // to allocate unique IDs on both without any locking.  All storage area ids
   // are allocated on the WebKit thread.
   int64 last_storage_area_id_;
   int64 last_session_storage_namespace_id_on_ui_thread_;
   int64 last_session_storage_namespace_id_on_io_thread_;
 
@@ skipping 22 matching lines @@
   // Maps ids to StorageNamespaces.  We own these objects.
   typedef std::map<int64, DOMStorageNamespace*> StorageNamespaceMap;
   StorageNamespaceMap storage_namespace_map_;
 
   scoped_refptr<quota::SpecialStoragePolicy> special_storage_policy_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(DOMStorageContext);
 };
 
 #endif  // CONTENT_BROWSER_IN_PROCESS_WEBKIT_DOM_STORAGE_CONTEXT_H_