1531455 - Limit the number of chrome Custom Elements that get loaded for GeckoView

Status: RESOLVED FIXED

(GeckoView :: General, enhancement, P3)

Description

[Brian Grinstead [:bgrins]]

As I understand it:

1. GeckoView creates a xul browser at https://searchfox.org/mozilla-central/rev/00f3836a87b844b5e4bc82f698c559b9966e4be2/mobile/android/chrome/geckoview/geckoview.js#376 via the script loaded in https://searchfox.org/mozilla-central/source/mobile/android/chrome/geckoview/geckoview.xul.
2. Because of (1), we must running the same MainProcessSingleton which loads Custom Elements via https://searchfox.org/mozilla-central/rev/00f3836a87b844b5e4bc82f698c559b9966e4be2/toolkit/components/processsingleton/MainProcessSingleton.jsm#58, since that's how the <xul:browser> Custom Element gets loaded.
3. There's no other chrome UI that requires Custom Elements in GeckoView.

I think we could expand the condition with which we skip loading non-browser Custom Elements to include geckoview.xul at https://searchfox.org/mozilla-central/rev/00f3836a87b844b5e4bc82f698c559b9966e4be2/toolkit/content/customElements.js#499. This would avoid loading and executing a bunch of JS for Custom Elements that are never used.

Comment 1

[Chris Peterson [:cpeterson]]

sounds like this change could improve GeckoView startup time.

Comment 2

[Barret Rennie [:barret] (they/them)]

:sefeng, did you file this under qf:p1 during your triage? Would you agree this is a qf:responsiveness bug, which would mean this probably would be a p3?

Comment 3

[Sean Feng [:sefeng][PTO, back July 1st]]

brennie: Yeah, I think I marked this qf:p1 during triage and I can't recall exactly how we made the decision. However, based on cpeterson's comment, it seems like the GeckoView startup time could be improved by limiting the number of Custom Elements, so I am not sure if responsiveness is the correct category for it.

Comment 4

[Chris Peterson [:cpeterson]]

I'm editing a bunch of GeckoView bugs. If you'd like to filter all this bugmail, search and destroy emails containing this UUID:

e88a5094-0fc0-4b7c-b7c5-aef00a11dbc9

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

This is marked as qf:p1. Chris, could you needinfo someone from GeckoView team to take a look at this?

Comment 6

[Chris Peterson [:cpeterson]]

(In reply to Olli Pettay [:smaug] from comment #5)

This is marked as qf:p1. Chris, could you needinfo someone from GeckoView team to take a look at this?

I'm no longer the EPM for GeckoView. Forwarding needinfo request to Emily Toop, GeckoView engineering manager. Also, flagging this bug (with whiteboard tag [geckoview]) so it shows up in the GeckoView triage meeting.

Comment 7

[Brendan Dahl [:bdahl]]

Attachment: Bug 1531455 - Don't load extra custom elements in GeckoView. r=bgrins

GeckoView only needs the browser element, skip loading the rest.

Comment 8

[Brendan Dahl [:bdahl]]

Did a quick test of creating 5 new tabs, timing from action_new_tab to DOMContentLoaded on a Moto G. Looks like it shaves off ~100ms.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ce08dcd4388f
Don't load extra custom elements in GeckoView. r=bgrins

Comment 10

[Nick Alexander :nalexander [he/him]]

(In reply to Brendan Dahl [:bdahl] from comment #8)

Did a quick test of creating 5 new tabs, timing from action_new_tab to DOMContentLoaded on a Moto G. Looks like it shaves off ~100ms.

My guess is that this is pure hotness for Bug 1608826. Thanks, bdahl!

Comment 11

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/ce08dcd4388f