Disallow resizing on OffscreenCanvas that has been transferred control from canvas

In my previous patch (https://codereview.chromium.org/2294963002/)
I had some primitive ideas about disallowing resizing on
OffscreenCanvas. This CL makes it more assertive by throwing
exception (not just causing no effect) to alert users.

BUG=563852

Review-Url: https://codereview.chromium.org/2330553002
Cr-Commit-Position: refs/heads/master@{#417951}
4 files changed