Right now there is only one mutator working on a heap and it can
therefore access the heap's weak maps without locking. The GC is the
only other user of the weak maps and it accesses it within a safepoint
operation scope.
Once we move the heap to the isolate group there can be concurrent
accesses to the weak maps. As a preparation step this CL adds locking
around the non-GC API.
Issue https://github.com/dart-lang/sdk/issues/36097
Change-Id: I84acce24612b12a7393154cab816f0eff9c7589a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/116201
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
6717bfe423