facebook/flow — pull request #113 by tcoopman (2014-11-24 08:06:35+00:00)
Title: type and endings in options are optional arguments for Blob constructor

According to https://developer.mozilla.org/en-US/docs/Web/API/Blob.Blob type and endings are optional arguments.
(http://dev.w3.org/2006/webapi/FileAPI/#dfn-BlobPropertyBag also says type is optional, but has no endings argument at all)