added backwards compatibility code to fill in missing title metadata in WeaveDataSource hierarchies.
added backwards compatibility code to fill in missing title metadata in
WeaveDataSource hierarchies.

Change-Id: Iaf088d25f60e3db873f219a9e940f1f1706f5f3d

WeaveTeam/WeaveJS,WeaveTeam/WeaveJS,WeaveTeam/WeaveJS,WeaveTeam/WeaveJS