In order to ensure proper ordering between fetches of blob URLs and revocation of a blob URL (specifically the case where a fetch is started, and right afterwards the URL is revoked) we need to move resolution of the blob URL into blink.
In the spec blob URLs are resolved at URL parsing time, so we'll likely end up having to do something similar. Currently this is only a problem in workers (as otherwise fetches and blob URL revocation both happen on channel-associated mojo pipes, so are properly ordered), but when blob URL handling is fully mojofied this will be a much bigger problem.
Comment 1 by mek@chromium.org
, Jan 10 2018