Support NodeFront in Node reps

[juliandescottes]

Currently investigating using Reps to display grid containers in the new Inspector Grid panel (Bug 1338298).

Most of the complex reps are expecting grips (generated from ObjectActors). But the inspector is usually dealing with NodeActors, not with ObjectActors.

Initially I wanted to add an actor method to instantiate an ObjectActor from a NodeActor. The more I investigate on this path the more it seems like ObjectActor & grips are tightly linked to the debugger domain. I thought grips were kind a of a generic/shared representation of values for actors, but I guess this was wrong.

@nchevobbe suggested two options:

• support NodeFront objects in ElementNode rep
• convert (as much as possible) NodeFront to grips on the client side

Given what I understand about ObjectActors and grips I am tempted to go for the 1st option: reps should not force callers to use grips. Regarding the callbacks onInspectIconClick & onDOMNodeMouseOver, they should be called with the object used to create the rep. Meaning that if you create an ElementNode rep using NodeFronts, the argument of your callbacks will be a NodeFront.

Thoughts @nchevobbe @janodvarko ?

[nchevobbe]

@juliandescottes is it still wanted ?
I'm moving reps to devtools-core and I was wondering if this is still valid.

[juliandescottes]

We have implemented workarounds everywhere for now, by converting NodeFronts to grips:

• http://searchfox.org/mozilla-central/rev/d441cb24482c2e5448accaf07379445059937080/devtools/client/inspector/boxmodel/components/ComputedProperty.js#28-59
• http://searchfox.org/mozilla-central/rev/d441cb24482c2e5448accaf07379445059937080/devtools/client/inspector/grids/components/GridItem.js#61-91

I think it would be nicer to have an actual support for NodeFronts. If we don't implement this, then let's open a bug in bugzilla to cleanup the duplicated translation linked above.

[nchevobbe]

Thanks @juliandescottes !
I moved the issue to firefox-devtools/devtools-core#411