There were options already being passed to BrowserTestUtils.removeTab, with only
a single property being observed, "dontRemove". This caused BrowserTestUtils.removeTab
to return a Promise once a tab is removed, but didn't actually remove the tab (as the
calling test would be responsible for that themselves). This patch removes that option,
and adds a method to BrowserTestUtils called tabRemoved to use for that case instead.
The options being passed to removeTab are now forwarded along directly to tabbrowser's
removeTab method.
MozReview-Commit-ID: JzfZuoZmlJ0
ffffc37dc6