Auto merge of #18549 - nnethercote:fix-enclosing-crash, r=heycam

Fix a panic in Stylo memory reporting.

`MallocSizeOfOps::enclosing_size_of_op` is an `Option<>` type, and the panic in
question is caused by not providing a value in a case where it's needed for
measuring a HashSet.

HashMaps and HashSets are common enough that it makes sense to make
`enclosing_size_of_op` non-optional, which this patch does.

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- [ ] These changes fix #__ (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [X] These changes do not require tests because tests are on the Gecko side.

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components/style/gecko/generated/bindings.rs

@@ -1898,7 +1898,10 @@ extern "C" {
     pub fn Servo_Element_ClearData(node: RawGeckoElementBorrowed);
 }
 extern "C" {
-    pub fn Servo_Element_SizeOfExcludingThisAndCVs(arg1: MallocSizeOf,
+    pub fn Servo_Element_SizeOfExcludingThisAndCVs(malloc_size_of:
+                                                       MallocSizeOf,
+                                                   malloc_enclosing_size_of:
+                                                       MallocSizeOf,
                                                    seen_ptrs: *mut SeenPtrs,
                                                    node:
                                                        RawGeckoElementBorrowed)
@@ -1964,6 +1967,8 @@ extern "C" {
 }
 extern "C" {
     pub fn Servo_StyleSheet_SizeOfIncludingThis(malloc_size_of: MallocSizeOf,
+                                                malloc_enclosing_size_of:
+                                                    MallocSizeOf,
                                                 sheet:
                                                     RawServoStyleSheetContentsBorrowed)
      -> usize;