Implement getDocumentStreamTypes() in DocumentsProvider.

According to the documentation, getStreamTypes() must return all streamable
MIME types. This CL takes the MIME types from COLUMN_MIME_TYPE as long as
the document is not virtual.

If the provider implements converters, then it should override
getDocumentStreamTypes.

Bug: 27156282
Change-Id: I9ab149e097600a470fc9be8f1270f68929fdf851
5 files changed