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 10cfe2d142f0fa6b340738512a56a94a66eca8eb..ab345506c13b7e1ccbd3200b97e0ccee81cfe184 100644
--- a/content/browser/dom_storage/dom_storage_context_impl.h
+++ b/content/browser/dom_storage/dom_storage_context_impl.h
@@ -22,13 +22,15 @@ 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();