This is a short term fix as part of ongoing discussions around tab strip UX for indicating tab state. A consensus has been reached that the throbber/spinner being displayed for background tabs is largely a source of visual noise during a session restore.
The UX team is in the middle of a full rethink of how to communicate tab state via the tab strip, especially in light of ongoing feature work around proactive tab discarding and staggered background-disposition tab opening. Expect more work here in the near future.
Comment 1 by chrisha@chromium.org
, Sep 5 2017