1597461 - Remove `getCrossProcessWrapperTag` CPOW logic

Status: RESOLVED DUPLICATE of bug 1620226

(Core :: DOM: Navigation, defect, P3)

Description

[Kannan Vijayan [:djvj]]

In file js/ipc/WrapperOwner.cpp

Checks if an incoming nsISupports is an nsIDocShellTreeItem (using QueryInterface), and if so returns a static string.

The only uses of this is to generate a tag string that is passed around places with CPOWs, and never really used by anyone except for equality checks relating to CPOWs.

This should likely change to simply checking for the nsIDocShell interface, and if so returning the literal string “ContentDocShell”

As nothing else reads that string (except the comparison operator), it’s unlikely that any tests will break if you change it.

Comment 1

[Chris Peterson [:cpeterson]]

Kannan says replacing nsIDocShellTreeItem calls should block enabling Fission in Nightly (M6).

Comment 2

[Nika Layzell [:nika] (ni? for response)]

There are no uses of getCrossProcessWrapperTag left in the tree, as far as I can tell, so we can probably remove the code related to it entirely. https://searchfox.org/mozilla-central/search?q=getCrossProcessWrapperTag&path=

Comment 3

[Chris Peterson [:cpeterson]]

Deferring to Fission M7 Beta because removing unused code doesn't need to block enabling Fission in Nightly.

Comment 4

[Andrew McCreight [:mccr8] (PTO until 12-2)]

This code was removed in bug 1620226.

Comment 5

[Chris Peterson [:cpeterson]]

Clearing Fission Milestone for bugs resolved as duplicates. We don't need to track duplicates.