new Headers(undefined) doesn't work with Samsung Internet 6.4

[jeffposnick]

Library Affected:
workbox-streams

I'm testing out a new site using workbox.streams with Samsung Internet 6.4, and found the following:

That's coming from

const headers = new Headers(headersInit);

Manually running

new Headers(undefined);

from within the Samsung Internet JS console leads to that same TypeError: Failed to construct 'Headers': No matching constructor signature.(…) error, so I guess Chromium 56 didn't support undefined as a parameter to the Headers constructor.