Persist sessionStorage on disk.

content/public/browser/dom_storage_context.h

 // Copyright (c) 2012 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_PUBLIC_BROWSER_DOM_STORAGE_CONTEXT_H_
 #define CONTENT_PUBLIC_BROWSER_DOM_STORAGE_CONTEXT_H_
 #pragma once
 
 #include <vector>
 
 #include "base/callback.h"
 #include "base/string16.h"
 #include "content/common/content_export.h"
 #include "webkit/dom_storage/dom_storage_context.h"
 
 class FilePath;
 
 namespace content {
 
 class BrowserContext;
+class SessionStorageNamespace;
 
 // Represents the per-BrowserContext Local Storage data.
 class DOMStorageContext {
  public:
   typedef base::Callback<
       void(const std::vector<dom_storage::DomStorageContext::UsageInfo>&)>
           GetUsageInfoCallback;
 
   // Returns a collection of origins using local storage to the given callback.
   virtual void GetUsageInfo(const GetUsageInfoCallback& callback) = 0;
 
   // Deletes the local storage data for the given origin.
   virtual void DeleteOrigin(const GURL& origin) = 0;
 
   // The stuff below is DEPRECATED.
   typedef base::Callback<void(const std::vector<FilePath>&)>
       GetAllStorageFilesCallback;
   virtual void GetAllStorageFiles(
       const GetAllStorageFilesCallback& callback) = 0;
   virtual FilePath GetFilePath(const string16& origin_id) const = 0;
   virtual void DeleteForOrigin(const string16& origin_id) = 0;
   virtual void DeleteLocalStorageFile(const FilePath& file_path) = 0;
 
+  // Called when the sessionStorage for |persistent_namespace_id| can safely be
+  // deleted (it won't be used by session restore).
+  virtual void DoomSessionStorage(
+      const std::string& persistent_namespace_id) = 0;
+
+  virtual scoped_refptr<SessionStorageNamespace> RecreateSessionStorage(
+      const std::string& persistent_id) = 0;
+
  protected:
   virtual ~DOMStorageContext() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_DOM_STORAGE_CONTEXT_H_