SessionStorageDatabase: Allow writing data into a shallow copy.

webkit/dom_storage/session_storage_database.h

Index: webkit/dom_storage/session_storage_database.h
diff --git a/webkit/dom_storage/session_storage_database.h b/webkit/dom_storage/session_storage_database.h
index 5230f370c4a3805c370bd130918f87cd265184a7..02446bbc68f82820bcebb352a2b2d3a9fd6e2344 100644
--- a/webkit/dom_storage/session_storage_database.h
+++ b/webkit/dom_storage/session_storage_database.h
@@ -44,7 +44,9 @@ class SessionStorageDatabase :
   // Updates the data for |namespace_id| and |origin|. Will remove all keys
   // before updating the database if |clear_all_first| is set. Then all entries
   // in |changes| will be examined - keys mapped to a null NullableString16 will
-  // be removed and all others will be inserted/updated as appropriate.
+  // be removed and all others will be inserted/updated as appropriate. It is
+  // allowed to write data into a shallow copy created by CloneNamespace, and in
+  // that case the copy will be made deep before writing the values.
   bool CommitAreaChanges(int64 namespace_id,
                          const GURL& origin,
                          bool clear_all_first,
@@ -158,6 +160,15 @@ class SessionStorageDatabase :
   // Deletes all values in |map_id|.
   bool ClearMap(const std::string& map_id, leveldb::WriteBatch* batch);
 
+  // Breaks the association between (|namespace_id|, |origin|) and |map_id| and
+  // creates a new map for (|namespace_id|, |origin|). Copies the data from the
+  // old map if |copy_data| is true.
+  bool DeepCopyArea(int64 namespace_id,
+                    const GURL& origin,
+                    bool copy_data,
+                    std::string* map_id,
+                    leveldb::WriteBatch* batch);
+
   // Helper functions for creating the keys needed for the schema.
   static std::string NamespaceStartKey(const std::string& namespace_id_str);
   static std::string NamespaceStartKey(int64 namespace_id,