Worker changes to prepare for lock-free shutdown.

sync/internal_api/public/engine/passive_model_worker.cc

Index: sync/internal_api/public/engine/passive_model_worker.cc
diff --git a/sync/internal_api/public/engine/passive_model_worker.cc b/sync/internal_api/public/engine/passive_model_worker.cc
index 10d20ee4f87be8773483ca2d8074283b0e76395f..17e45fc4a7d194f024d268003c4202f01e532199 100644
--- a/sync/internal_api/public/engine/passive_model_worker.cc
+++ b/sync/internal_api/public/engine/passive_model_worker.cc
@@ -8,14 +8,22 @@
 
 namespace syncer {
 
-PassiveModelWorker::PassiveModelWorker(const MessageLoop* sync_loop)
-    : sync_loop_(sync_loop) {}
+PassiveModelWorker::PassiveModelWorker(const MessageLoop* sync_loop,
+                                       WorkerObserver* observer)
+    : ModelSafeWorker(observer),
+      sync_loop_(sync_loop) {
+}
 
 PassiveModelWorker::~PassiveModelWorker() {
 }
 
+void PassiveModelWorker::RegisterForLoopDestruction() {
+  NOTREACHED();
+}
+
 SyncerError PassiveModelWorker::DoWorkAndWaitUntilDone(
-    const WorkCallback& work) {
+    const WorkCallback& work,
+    base::WaitableEvent* done) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
   // Simply do the work on the current thread.
   return work.Run();