Persist sessionStorage on disk.

content/browser/dom_storage/dom_storage_context_impl.h

Index: content/browser/dom_storage/dom_storage_context_impl.h
diff --git a/content/browser/dom_storage/dom_storage_context_impl.h b/content/browser/dom_storage/dom_storage_context_impl.h
index 135b0c52d21fbe22d3d2e493cc10f31d83f02ae7..481084ddbc64ef6e4d396cf56b9dfc0c14e65420 100644
--- a/content/browser/dom_storage/dom_storage_context_impl.h
+++ b/content/browser/dom_storage/dom_storage_context_impl.h
@@ -23,13 +23,15 @@ class CONTENT_EXPORT DOMStorageContextImpl :
  public:
   // If |data_path| is empty, nothing will be saved to disk.
   DOMStorageContextImpl(const FilePath& data_path,
-                        quota::SpecialStoragePolicy* special_storage_policy);
+                        quota::SpecialStoragePolicy* special_storage_policy,
+                        bool save_session_storage_on_disk);
 
   // DOMStorageContext implementation.
   virtual void GetUsageInfo(const GetUsageInfoCallback& callback) OVERRIDE;
   virtual void DeleteOrigin(const GURL& origin) OVERRIDE;
   virtual scoped_refptr<content::SessionStorageNamespace>
       RecreateSessionStorage(const std::string& persistent_id) OVERRIDE;
+  virtual void StartScavengingUnusedSessionStorage() OVERRIDE;
 
   // Called to free up memory that's not strictly needed.
   void PurgeMemory();