[IDBObservers] Moving options from constructor to .observe call.

Per spec change in
https://github.com/WICG/indexed-db-observers/commit/5aa4abc288ef526801797d3a9209ac0da8e359e7.

I'm also adding more exceptions here, as per
https://github.com/WICG/indexed-db-observers/commit/7723586ef6e5663739ae4800f1e6a7172296f67c.

R=cmumford
BUG=655865

Review-Url: https://codereview.chromium.org/2459113002
Cr-Commit-Position: refs/heads/master@{#430779}