Auto merge of #23045 - miller-time:promote-memory-blob, r=jdm

create uuid before sending PromoteMemory message

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When `Blob::promote` is promoting a `BlobImpl::Memory`, create uuid and send it with the `FileManagerThreadMsg::PromoteMemory` message rather than blocking until one is received.

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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 #23032  (GitHub issue number if applicable)

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- [X] There are tests for these changes OR
- [ ] These changes do not require tests because ___

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components/script/dom/blob.rs

@@ -238,23 +238,17 @@ impl Blob {
             bytes: bytes.to_vec(),
         };
 
-        let (tx, rx) = ipc::channel(self.global().time_profiler_chan().clone()).unwrap();
-        let msg = FileManagerThreadMsg::PromoteMemory(blob_buf, set_valid, tx, origin.clone());
+        let id = Uuid::new_v4();
+        let msg = FileManagerThreadMsg::PromoteMemory(id, blob_buf, set_valid, origin.clone());
         self.send_to_file_manager(msg);
 
-        match rx.recv().unwrap() {
-            Ok(id) => {
-                *self.blob_impl.borrow_mut() = BlobImpl::File(FileBlob {
-                    id: id.clone(),
-                    name: None,
-                    cache: DomRefCell::new(Some(bytes.to_vec())),
-                    size: bytes.len() as u64,
-                });
-                id
-            },
-            // Dummy id
-            Err(_) => Uuid::new_v4(),
-        }
+        *self.blob_impl.borrow_mut() = BlobImpl::File(FileBlob {
+            id: id.clone(),
+            name: None,
+            cache: DomRefCell::new(Some(bytes.to_vec())),
+            size: bytes.len() as u64,
+        });
+        id
     }
 
     /// Get a FileID representing sliced parent-blob content