1490810 - Simulate Fission for browser actors by blocking them from receiving subframe events

Status: RESOLVED FIXED

(Firefox :: General, enhancement, P3)

Description

[:Felipe Gomes (needinfo for replies!)]

We want to have a pref, then an opt-in mechanism, and then an opt-out mechanism to allow us to write code in the browser actors in a Fission-compatible way.

One of the main things that will change is that priviliged JS code (such as the code in frame scripts and actors) receive events from subframes, whereas that won't happen anymore with Fission.

So we want to have a mechanism to simulate this in order to allow us to write code in a fission compatible way (and later prevent Fission-incompatible code from being landed).


The idea for now is to make the ActorManagerChild to not forward the events to the actors unless it's for an actor related to frame.

Another thing that will need to change is that, during construction, a lot of the actors register listeners directly with the message manager (`this.mm.addEventListeners`), and we're planning on adding an addEventListener method to the ActorChild class to intercept this  (in the same manner that the pre-declared listeners work)

Comment 1

[:Felipe Gomes (needinfo for replies!)]

Attachment: Bug 1490810 - Simulate Fission for browser actors by blocking them from receiving sub-frame events. r=kmag

If the pref browser.fission.simulate is true, the event dispatcher in ActorManagerChild will not dispatch events to actors that aren't associated with the same window as the event's target.

In addition, when that pref is on, the actors associated with sub-frames will have their content property bound to the correct content window, that might differ from the message manager's window (which is always related to the top level).

Then, in order to write Fission-compatible code, that specific actor will need to be declared with allFrames = true, meaning that it wants to be instantiated for every frame, and not just top-level ones

Comment 2

[Kris Maglione [:kmag]]

Comment on attachment 9010525 [details]
Bug 1490810 - Simulate Fission for browser actors by blocking them from receiving sub-frame events. r=kmag

Kris Maglione [:kmag] has approved the revision.

Comment 3

[:Felipe Gomes (needinfo for replies!)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=71c26f0dd803faa9b4f89990e4111302ba42a4f9

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3339b4bf9acd
Simulate Fission for browser actors by blocking them from receiving sub-frame events. r=kmag

Comment 5

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/3339b4bf9acd

Comment 6

[:Felipe Gomes (needinfo for replies!)]

FWIW I sent to tryserver a patch toggling this pref on to see what would fail:

https://treeherder.mozilla.org/#/jobs?repo=try&revision=3f7edc779f2f8a95f9caddcb48770f74369d8726

Lots of failures, but very interesting results.. I looked at several of the failures and they were as expected: context menu failures, accessing the wrong content, timing out waiting for events, etc.

Looks like this will be very useful to guide the work to make these features Fission-compatible

Comment 7

[Chris Peterson [:cpeterson]]

Retroactively moving fixed bugs whose summaries mention "Fission" (or other Fission-related keywords) but are not assigned to a Fission Milestone to an appropriate Fission Milestone.

This will generate a lot of bugmail, so you can filter your bugmail for the following UUID and delete them en masse:

0ee3c76a-bc79-4eb2-8d12-05dc0b68e732