1317691 - Make aRelatedToCurrent / _lastRelatedTab deal with async-inited calls that open tabs

Status: NEW

(Firefox :: Tabbed Browser, defect, P3)

Description

[:Gijs (he/him)]

aRelatedToCurrent will use the tabbrowser's _lastRelatedTab, or the selected tab if no related tab is set, to insert new tabs directly next to the selected / "related" tab if set. This is what causes e.g. middle-clicking a number of links in succession to open next to each other (assuming they load in the background).

In principle, if the action that triggers this is async then it is possible for the actual openLinkIn / loadOneTab / addTab code to run after the selected/related tab has changed, causing the related/selected tab to not be the tab at which the action was started. To avoid this problem, we could make consumers pass in the related tab instead of relying on the related/selected tab to still be the same by the time the code runs. This would be similar to the fix in bug 1000458 that passed in the browser to use for a "current" openLinkIn load.