Alexandre Poirot [:ochameau] Reporter
	Description • 6 years ago

Bug 1222047 introduced a generic API to instantiate fronts, but it doesn't allow to listen for fronts being created.
It would be really helpful to expose such API in order to easily register event listeners whenever a front get created, that, without forcing the instantiation of a new one.

The typical usecase is the toolbox class. It has to listen for some events on the performance and inspector-related fronts, but these fronts don't necessarily have to be instantiated on toolbox opening. They will be created depending on which panel we open. For now, in order to mitigate that, we managed these fronts creation from toolbox. But for fission we have to uncouple that from the toolbox, instead it should be handled by the target or the root fronts. In addition to that, we will start instantiating more than just one of these actors and so it will be handy to have a way to listen for all the new ones being created.

So TabTarget.getFront:
  https://searchfox.org/mozilla-central/rev/819cd31a93fd50b7167979607371878c4d6f18e8/devtools/client/framework/target.js#363-373
and RootClient.getFront:
  https://searchfox.org/mozilla-central/rev/819cd31a93fd50b7167979607371878c4d6f18e8/devtools/shared/client/root-client.js#277-293
Should both emit an event whenever a new front is created. This event should be easily listened by typeName as listeners will most likely care about one particular type of front.
We might also want to emit an event on destruction (if that is *really* useful as fronts are going to be destroyed anyway and there is no value to do it only for removing the listeners).

	Yulia Startsev [:yulia] | Back in Oct. Assignee
	Comment 1 • 6 years ago

this change only impacts the target front, and emits an event every time a target is
created. No listners yet.

	Pulsebot
	Comment 2 • 6 years ago

Pushed by ystartsev@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/587532e4c6fe
emit event when target scoped front is created; r=ochameau

	Dorel Luca [:dluca]
	Comment 3 • 6 years ago
bugherder

https://hg.mozilla.org/mozilla-central/rev/587532e4c6fe