Reverse the dependency between selectors and malloc_size_of

components/selectors/parser.rs

@@ -266,7 +266,7 @@ where
 /// off the upper bits) at the expense of making the fourth somewhat more
 /// complicated to assemble, because we often bail out before checking all the
 /// hashes.
-#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq)]
 pub struct AncestorHashes {
     pub packed_hashes: [u32; 3],
 }