DOM: Fix Observable#from() [Symbol.iterator] semantics (1/2)
See WICG/observable#160, which specs the
Observable#from() semantics, matching these tests. See also
https://crbug.com/363015168 which describes the ways in which our
current implementation of Observable#from()'s detection semantics
are overbroad.
This CL makes the implementation of the "detection semantics" match the
desired behavior outlined in that issue, and adds a bunch of tests.
Bug: 363015168, 40282760
Change-Id: Id6cfdd45c44286b298e107635e4283b018f50aaf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5824955
Commit-Queue: Dominic Farolino dom@chromium.org
Reviewed-by: Mason Freed masonf@chromium.org
Cr-Commit-Position: refs/heads/main@{#1349019}