[FileAPI] Not expose FileReaderSync to service worker (#16)

Service worker by its nature doesn't want to initiate any sync requests within its context. It'll be nice if it's explicitly defined in FileReaderSync interface: [Exposed=DedicatedWorker,SharedWorker].

The corresponding service worker issue: https://github.com/slightlyoff/ServiceWorker/issues/735.

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/FileAPI/issues/16