Restore sessionStorage when chrome restarts.

content/browser/in_process_webkit/webkit_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_WEBKIT_CONTEXT_H_
 #define CONTENT_BROWSER_IN_PROCESS_WEBKIT_WEBKIT_CONTEXT_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 59 matching lines @@
   // last modified on or after the following time.
   void DeleteDataModifiedSince(const base::Time& cutoff);
 
   // Delete the session storage namespace associated with this id.  Can be
   // called from any thread.
   void DeleteSessionStorageNamespace(int64 session_storage_namespace_id);
 
   // Tells all children to not do delete data when destructed.
   void SaveSessionState();
 
+  // Tells DOMStorageContext to delete all session storages except the ones in
+  // |needed_session_storages|.
+  void DeleteUnneededSessionStorages(
+      const std::set<std::string>& needed_session_storages);
+
  private:
   friend class base::RefCountedThreadSafe<WebKitContext>;
   virtual ~WebKitContext();
 
   // Copies of browser context data that can be accessed on any thread.
   const FilePath data_path_;
   const bool is_incognito_;
 
   // True if the destructors of context objects should delete their files.
   bool clear_local_state_on_exit_;
 
   scoped_ptr<DOMStorageContext> dom_storage_context_;
   scoped_refptr<IndexedDBContext> indexed_db_context_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(WebKitContext);
 };
 
 #endif  // CONTENT_BROWSER_IN_PROCESS_WEBKIT_WEBKIT_CONTEXT_H_