Add native support for FinalizerList.makeCircularListIfUnenqueued

Called from FinalizerReference.enqueueSentinelReference to prevent
a race where the GC updates pendingNext of the sentinel reference
before enqueueSentinelReference.

Bug: 17462553

(cherry picked from commit 3256166df40981f1f1997a5f00303712277c963f)

Change-Id: I7ad2fd250c2715d1aeb919bd548ef9aab24f30a2

1 files changed, 2 insertions, 3 deletions

diff --git a/runtime/gc/reference_queue.cc b/runtime/gc/reference_queue.cc
index c3931e8bdc..4003524e5e 100644
--- a/runtime/gc/reference_queue.cc
+++ b/runtime/gc/reference_queue.cc
@@ -25,13 +25,12 @@
 namespace art {
 namespace gc {
 
-ReferenceQueue::ReferenceQueue()
-    : lock_("reference queue lock"), list_(nullptr) {
+ReferenceQueue::ReferenceQueue(Mutex* lock) : lock_(lock), list_(nullptr) {
 }
 
 void ReferenceQueue::AtomicEnqueueIfNotEnqueued(Thread* self, mirror::Reference* ref) {
   DCHECK(ref != NULL);
-  MutexLock mu(self, lock_);
+  MutexLock mu(self, *lock_);
   if (!ref->IsEnqueued()) {
     EnqueuePendingReference(ref);
   }