Persist sessionStorage on disk.

content/browser/dom_storage/session_storage_namespace_impl.cc

Index: content/browser/dom_storage/session_storage_namespace_impl.cc
diff --git a/content/browser/dom_storage/session_storage_namespace_impl.cc b/content/browser/dom_storage/session_storage_namespace_impl.cc
index 6ec762d5d2d706206d4f50d350a6aadae9d11ce8..eae9f27a1f67e39038ef68b11b1881d79493d378 100644
--- a/content/browser/dom_storage/session_storage_namespace_impl.cc
+++ b/content/browser/dom_storage/session_storage_namespace_impl.cc
@@ -14,10 +14,21 @@ SessionStorageNamespaceImpl::SessionStorageNamespaceImpl(
     : session_(new DomStorageSession(context->context())) {
 }
 
+SessionStorageNamespaceImpl::SessionStorageNamespaceImpl(
+    DOMStorageContextImpl* context,
+    const std::string& persistent_id)
+    : session_(new DomStorageSession(context->context(),
+                                     persistent_id)) {
+}
+
 int64 SessionStorageNamespaceImpl::id() const {
   return session_->namespace_id();
 }
 
+std::string SessionStorageNamespaceImpl::persistent_id() const {
+  return session_->persistent_namespace_id();
+}
+
 SessionStorageNamespaceImpl* SessionStorageNamespaceImpl::Clone() {
   return new SessionStorageNamespaceImpl(session_->Clone());
 }