Allows object evaluation in devtools -- Closes #6724

[HarryLovesCode]

The purpose of this is to fix how objects were previously evaluated in
the developer tools.

• Before this, evaluating an object such as the window would panic!
• After this, evaluating an object such as the window outputs [object Window]

A few things to note:

• This commit contains unsafe code.
• This does not contain a test because the developer tools cannot be properly tested until #5971 lands.

[highfive]

Warning

• These commits modify unsafe code. Please review it carefully!

[Ms2ger]

r? @jdm

[jdm]

Great work @HarryLovesCode! A few small changes and this should be ready to merge :)
-S-awaiting-review +S-needs-code-changes

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Reviewed 5 of 5 files at r1.
Review status: 4 of 5 files reviewed at latest revision, 10 unresolved discussions, all commit checks successful.

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^{components/devtools/actors/object.rs, line 23 [r1] (raw file):}
This should be Ok(false) since we don't actually handle any messages.

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^{components/devtools/lib.rs, line 47 [r1] (raw file):}
nit: add this in alphabetical order (and move the network_event import appropriately)

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^{components/devtools/lib.rs, line 79 [r1] (raw file):}
nit: add this in alphabetical order (and move network_event appropriately)

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^{components/devtools/lib.rs, line 222 [r1] (raw file):}
No need for this.

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^{components/devtools/lib.rs, line 262 [r1] (raw file):}
No need for this.

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^{components/devtools_traits/lib.rs, line 80 [r1] (raw file):}
Let's make this ActorValue { class: String, uuid: String } for clarity.

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^{components/script/devtools.rs, line 27 [r1] (raw file):}
nit: add uuid after the std imports.

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^{components/script/devtools.rs, line 47 [r1] (raw file):}
Let's keep this as else { with the assert.

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^{components/script/devtools.rs, line 48 [r1] (raw file):}
Let's just wrap about the ObjectClassName call instead of the whole block.

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^{components/script/devtools.rs, line 50 [r1] (raw file):}
This can be rval.handle() instead of creating one by hand.

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Comments from the review on Reviewable.io

[HarryLovesCode]

Review status: 4 of 5 files reviewed at latest revision, 2 unresolved discussions, all commit checks successful.

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^{components/devtools/lib.rs, line 222 [r1] (raw file):}
I think this review is on a previous commit. Already removed this.

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^{components/devtools/lib.rs, line 262 [r1] (raw file):}
I think this review is on a previous commit. Already removed this.

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Comments from the review on Reviewable.io

[HarryLovesCode]

Review status: 4 of 5 files reviewed at latest revision, all discussions resolved, all commit checks successful.

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^{components/script/devtools.rs, line 50 [r1] (raw file):}
I'm not sure about this. rval.handle() is of type js::jsapi::Handle<js::jsapi::Value> and ObjectClassName expects this type: js::jsapi::Handle<*mut js::jsapi::JSObject>. (Sorry about any typos. Reviewable keeps scrolling everytime I press a key)

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Comments from the review on Reviewable.io

[jdm]

You are correct.

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Reviewed 1 of 1 files at r2.
Review status: all files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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Comments from the review on Reviewable.io

[jdm]

Review status: all files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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^{components/script/devtools.rs, line 50 [r1] (raw file):}
Oh, my mistake. Then I'd prefer

let obj = RootedObject::new(cx, rval.get().to_object());
let class_name = ObjectClassName(cx, obj.handle());

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Comments from the review on Reviewable.io

[HarryLovesCode]

ping @jdm

[jdm]

@bors-servo: r+
Thanks for the patch!

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Reviewed 5 of 5 files at r3.
Review status: all files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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Comments from the review on Reviewable.io

[bors-servo]

📌 Commit e0f007a has been approved by jdm

[bors-servo]

⌛ Testing commit e0f007a with merge f75f019...

[bors-servo]

💔 Test failed - mac2

[HarryLovesCode]

The mac2 machine failed before compilation even began. Can we rerun that?

[metajack]

@bors-servo retry

• failed during git checkout

[bors-servo]

⌛ Testing commit e0f007a with merge f77973c...

[bors-servo]

☀️ Test successful - android, gonk, linux1, linux2, mac1, mac2, mac3