[Sync] Avoid unregistering object IDs on shutdown

chrome/browser/sync/glue/bridged_sync_notifier.h

Index: chrome/browser/sync/glue/bridged_sync_notifier.h
diff --git a/chrome/browser/sync/glue/bridged_sync_notifier.h b/chrome/browser/sync/glue/bridged_sync_notifier.h
index f48d0f9daaafe7d032517d055c9bab092f11eccd..26ab68a3011f757b6f8f8bbbf31bfd6157017aad 100644
--- a/chrome/browser/sync/glue/bridged_sync_notifier.h
+++ b/chrome/browser/sync/glue/bridged_sync_notifier.h
@@ -29,7 +29,9 @@ class BridgedSyncNotifier : public syncer::SyncNotifier {
 
   // SyncNotifier implementation. Passes through all calls to the delegate.
   // UpdateRegisteredIds calls will also be forwarded to the bridge.
-  virtual void UpdateRegisteredIds(syncer::SyncNotifierObserver* handler,
+  virtual void SetHandler(const std::string& handler_name,

[msw, 2012/08/07 20:09:30]

When a Handler wants to unregister itself in this paradigm, it'll call
SetHandler("Foo", NULL), but what if another handler has taken over "Foo"? Using
strings seems easily vulnerable to unintended actions like unregistering another
handler when you try to unregister yourself.

What's the reasoning behind this approach and are you concerned about this extra
level of complication/indirection?

+                          syncer::SyncNotifierObserver* handler) OVERRIDE;
+  virtual void UpdateRegisteredIds(const std::string& handler_name,
                                    const syncer::ObjectIdSet& ids) OVERRIDE;
   virtual void SetUniqueId(const std::string& unique_id) OVERRIDE;
   virtual void SetStateDeprecated(const std::string& state) OVERRIDE;