strategySizeAlgorithm validation in WritableStreamDefaultControllerGetChunkSize

[daeyeon]

What is the issue with the Streams Standard?

Hi, while reviewing an issue in Node.js, I noticed a case where the stream's state is 'closed' when getting the chunk size, after the sizeAlgorithm has been cleared.

i. writableStreamDefaultWriterClose
ii. writableStreamClose
iii. writableStreamDefaultControllerClose
iv. writableStreamDefaultControllerAdvanceQueueIfNeeded
v. WritableStreamDefaultControllerProcessClose(controller)

6. Perform ! WritableStreamDefaultControllerClearAlgorithms(controller).

4. Set controller.[[strategySizeAlgorithm]] to undefined.

7.1. Perform ! WritableStreamFinishInFlightClose(stream).

7. Set stream.[[state]] to "closed".

However, the current assertion below only checks erroring or errored states.

WritableStreamDefaultControllerGetChunkSize(controller, chunk) performs the following steps:

1. If controller.[[strategySizeAlgorithm]] is undefined, then:
   1.1. Assert: controller.[[stream]].[[state]] is "erroring" or "errored".
   1.2. Return 1.

[domenic]

This is a consequence of 86d07e9.

Presumably we should just widen the assertion, but also be sure to add a test while we're doing so.