1049548 - Make async tab switching rejections send rejection notices to the error console

Status: NEW

(Firefox :: Tabbed Browser, defect, P3)

Description

[Mike Conley (:mconley) (:⚙️)]

Bug 1009628 made Firefox tab switching asynchronous when using an e10s window. In the event that a tab switch bails out (we switch back to the original tab before the MozAfterRemotePaint fires), we reject the Promise that tabbrowser.xml's "_prepareForTabSwitch" method returns.

Right now, when that Promise rejects, we just silently bail out of the deck switching code. This ended up masking a problem where an exception being thrown inside one of the Promises caused tab switching to silently break.

We should log tab switching rejections to the error console - at least, the unexpected ones.