Mask OOBE when filtering recent documents.

There is a data ownership issue related to recent documents Cursors,
and the loader and UI threads can end up traversing the same Cursor
at runtime.  This change masks OOBE crashes caused by this race until
we have time to fix cleanly.

Bug: 11736668
Change-Id: I2039a5edcf341fcaedacc2f08bde96fc5a271782