Add Service ID zones to service protocol

runtime/vm/object_id_ring_test.cc

Index: runtime/vm/object_id_ring_test.cc
diff --git a/runtime/vm/object_id_ring_test.cc b/runtime/vm/object_id_ring_test.cc
index 745ec14a30bc59b23ebacf1ef41079fc7d428795..4cb1f3bd01997d32cacfd75e7125b3d1c7ea66dd 100644
--- a/runtime/vm/object_id_ring_test.cc
+++ b/runtime/vm/object_id_ring_test.cc
@@ -112,8 +112,15 @@ TEST_CASE(ObjectIdRingScavengeMoveTest) {
   EXPECT_NE(Object::null(), raw_obj);
   intptr_t raw_obj_id1 = ring->GetIdForObject(raw_obj);
   EXPECT_EQ(0, raw_obj_id1);
+  // Get id 0 again.
+  EXPECT_EQ(raw_obj_id1,
+      ring->GetIdForObject(raw_obj, ObjectIdRing::kExistingOrNewId));
+  // Add to ring a second time.
   intptr_t raw_obj_id2 = ring->GetIdForObject(raw_obj);
   EXPECT_EQ(1, raw_obj_id2);
+  // Get id 0 again.
+  EXPECT_EQ(raw_obj_id1,
+      ring->GetIdForObject(raw_obj, ObjectIdRing::kExistingOrNewId));
   RawObject* raw_obj1 = ring->GetObjectForId(raw_obj_id1, &kind);
   EXPECT_EQ(ObjectIdRing::kValid, kind);
   RawObject* raw_obj2 = ring->GetObjectForId(raw_obj_id2, &kind);
@@ -142,6 +149,9 @@ TEST_CASE(ObjectIdRingScavengeMoveTest) {
   EXPECT(Dart_IsList(moved_handle));
   EXPECT_VALID(Dart_ListLength(moved_handle, &list_length));
   EXPECT_EQ(3, list_length);
+  // Test id reuse.
+  EXPECT_EQ(raw_obj_id1,
+      ring->GetIdForObject(raw_object_moved1, ObjectIdRing::kExistingOrNewId));
 }