Worker changes to prepare for lock-free shutdown.

chrome/browser/sync/glue/sync_backend_registrar.h

Index: chrome/browser/sync/glue/sync_backend_registrar.h
diff --git a/chrome/browser/sync/glue/sync_backend_registrar.h b/chrome/browser/sync/glue/sync_backend_registrar.h
index f43e2791318838fe54e9e2db9269c73886c065ab..31b13108ba5332f9da26819034ed38a8384e3a7a 100644
--- a/chrome/browser/sync/glue/sync_backend_registrar.h
+++ b/chrome/browser/sync/glue/sync_backend_registrar.h
@@ -34,7 +34,8 @@ class UIModelWorker;
 // A class that keep track of the workers, change processors, and
 // routing info for the enabled sync types, and also routes change
 // events to the right processors.
-class SyncBackendRegistrar : public syncer::SyncManager::ChangeDelegate {
+class SyncBackendRegistrar : public syncer::SyncManager::ChangeDelegate,
+                             public syncer::WorkerLoopDestructionObserver {
  public:
   // |name| is used for debugging.  Does not take ownership of |profile| or
   // |sync_loop|.  Must be created on the UI thread.
@@ -108,6 +109,9 @@ class SyncBackendRegistrar : public syncer::SyncManager::ChangeDelegate {
   void GetWorkers(std::vector<syncer::ModelSafeWorker*>* out);
   void GetModelSafeRoutingInfo(syncer::ModelSafeRoutingInfo* out);
 
+  // syncer::WorkerLoopDestructionObserver implementation.
+  virtual void OnWorkerLoopDestroyed(syncer::ModelSafeGroup group) OVERRIDE;
+
  private:
   typedef std::map<syncer::ModelSafeGroup,
                    scoped_refptr<syncer::ModelSafeWorker> > WorkerMap;