986503 - Merge CustomizableUI.jsm and CustomizableWidgets.jsm to reduce compartment overhead

Status: NEW

(Firefox :: Toolbars and Customization, defect)

Description

[Mike Conley (:mconley) (:⚙️) (PTO: May 24 - June 2nd)]

In bug 860642, we split out the widget definitions from CustomizableUI.jsm into CustomizableWidgets.jsm in an effort to reduce the complexity of CustomizableUI.jsm.

The JSM route was chosen arbitrarily by myself[1]. Maybe we should try doing a preprocessing include instead?

According to https://groups.google.com/forum/#!topic/mozilla.dev.platform/sAuhWQOAWic, CustomizableUI and CustomizableWidgets are new compartments contributing to the creeping start-up memory usage.

[1]: https://bugzilla.mozilla.org/show_bug.cgi?id=860642#c2

Comment 1

[Eric Rahm [:erahm]]

Mike, what do you mean by preprocessing include here? As in just |#include "CustomizableWidgets.jsm"|? I'm happy to try it out and see if there's any memory improvement.

Comment 2

[(Away until May 24) Jared Wein [:jaws] (please needinfo? me)]

Yeah, that would be sufficient. Though the final patch we may want to rename from CustomizableWidgets.jsm to CustomizableWidgets.inc.jsm to make it clear that the file is included, like we do for tabs.inc.css, etc.

Keeping .jsm at the end helps with syntax highlighting by editors.

Comment 3

[Matthew N. [:MattN]]

The other option is loadSubScript which has the advantage of not needing a build step on OSs which use symlinks for the object directory. This means you can simply restart the browser after editing without needing to build.