1715773 - Get rid of about:newtab preloaded browser content process workarounds

Status: RESOLVED FIXED

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

Description

[Mike Conley (:mconley) (:⚙️)]

I stumbled across this chunk of code today: https://searchfox.org/mozilla-central/rev/2c991232499e826e46f9d976eb653817340ba389/docshell/base/nsDocShell.cpp#12769

and it reminded me that before we had the dedicated Privileged About Content Process for about:newtab, we used to load it in a normal content process. Couple this with the fact that we have this perceived performance optimization where we preload an about:newtab in the background to make the next tab opening faster, this meant that sometimes users would have a new extra web content process opened and taking up resources for that background about:newtab.

Before we had the Privileged About Content Process, we worked around this resource problem by forcing about:newtab to load in a pre-existing content process, and then making sure that any navigation away from about:newtab results in an opportunity to create a new process. It was hacky, but it worked at the time. See bug 1376895.

Fast-forward to now. We have the Privileged About Content Process. Every about:newtab will necessarily load in that content process, and a bunch of mechanisms are in place to make sure that a navigation to a normal web page will result in that page loading in a normal content process and not the Privileged About Content Process.

So I think the preload hackery that was added in bug 1376895 can probably be removed now.

Comment 1

[Chris Peterson [:cpeterson]]

P3. This would be a nice cleanup.

Comment 2

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

Attachment: Bug 1715773 - Remove preloaded newtab process selection logic, r=mconley

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e89d64559e5b
Remove preloaded newtab process selection logic, r=mconley

Comment 4

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/e89d64559e5b