Auto merge of #23253 - BartGitHub:refactor-promise-compartment, r=jdm

Refactor promise compartment

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This PR adds a mechanism to verify that certain code is executed inside a ```JSAutoCompartment```, and applies this to the ```Promise::new_in_current_compartment``` constructor.

r? @jdm

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #23167

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- [x] These changes do not require tests because they do not change existing functionality.

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1 files changed, 6 insertions, 2 deletions

diff --git a/components/script/body.rs b/components/script/body.rs
index 9285fd110d2..1e18bc565a6 100644
--- a/components/script/body.rs
+++ b/components/script/body.rs
@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use crate::compartments::{AlreadyInCompartment, InCompartment};
 use crate::dom::bindings::codegen::Bindings::FormDataBinding::FormDataMethods;
 use crate::dom::bindings::error::{Error, Fallible};
 use crate::dom::bindings::reflector::DomObject;
@@ -49,9 +50,12 @@ pub enum FetchedData {
 
 // https://fetch.spec.whatwg.org/#concept-body-consume-body
 #[allow(unrooted_must_root)]
-#[allow(unsafe_code)]
 pub fn consume_body<T: BodyOperations + DomObject>(object: &T, body_type: BodyType) -> Rc<Promise> {
-    let promise = unsafe { Promise::new_in_current_compartment(&object.global()) };
+    let in_compartment_proof = AlreadyInCompartment::assert(&object.global());
+    let promise = Promise::new_in_current_compartment(
+        &object.global(),
+        InCompartment::Already(&in_compartment_proof),
+    );
 
     // Step 1
     if object.get_body_used() || object.is_locked() {