[Sync] Enable adding notifier observers from ProfileSyncService

chrome/browser/sync/profile_sync_service.h

Index: chrome/browser/sync/profile_sync_service.h
diff --git a/chrome/browser/sync/profile_sync_service.h b/chrome/browser/sync/profile_sync_service.h
index ef5eff0c9382fa1936b18ef0a068a38efb8e531f..5d225df0ba0e877d4491e05ec30c67eaf5a86b05 100644
--- a/chrome/browser/sync/profile_sync_service.h
+++ b/chrome/browser/sync/profile_sync_service.h
@@ -38,6 +38,7 @@
 #include "sync/internal_api/public/util/experiments.h"
 #include "sync/internal_api/public/util/unrecoverable_error_handler.h"
 #include "sync/js/sync_js_controller.h"
+#include "sync/notifier/sync_notifier_helper.h"
 
 class Profile;
 class ProfileSyncComponentsFactory;
@@ -253,6 +254,14 @@ class ProfileSyncService : public browser_sync::SyncFrontend,
   virtual bool HasSyncSetupCompleted() const;
   virtual void SetSyncSetupCompleted();
 
+  // syncer::SyncNotifier implementation (via SyncFrontend).
+  virtual void OnNotificationsEnabled() OVERRIDE;
+  virtual void OnNotificationsDisabled(
+      syncer::NotificationsDisabledReason reason) OVERRIDE;
+  virtual void OnIncomingNotification(
+      const syncer::ObjectIdPayloadMap& id_payloads,
+      syncer::IncomingNotificationSource source) OVERRIDE;
+
   // SyncFrontend implementation.
   virtual void OnBackendInitialized(
       const syncer::WeakHandle<syncer::JsBackend>& js_backend,
@@ -542,6 +551,16 @@ class ProfileSyncService : public browser_sync::SyncFrontend,
   // been cleared yet. Virtual for testing purposes.
   virtual bool waiting_for_auth() const;
 
+  // Updates the set of ObjectIds associated with a given
+  // |handler|. Passing an empty ObjectIdSet will unregister
+  // |handler|. There should be at most one handler registered per
+  // object id.
+  //
+  // The handler -> registered ids map is persisted across restarts of
+  // sync.
+  void UpdateRegisteredIds(syncer::SyncNotifierObserver* handler,
+                           const syncer::ObjectIdSet& ids);
+
   // ProfileKeyedService implementation.
   virtual void Shutdown() OVERRIDE;
 
@@ -816,6 +835,12 @@ class ProfileSyncService : public browser_sync::SyncFrontend,
   // Factory the backend will use to build the SyncManager.
   syncer::SyncManagerFactory sync_manager_factory_;
 
+  // The set of all registered IDs.
+  syncer::ObjectIdSet all_registered_ids_;
+
+  // Dispatches invalidations to handlers.
+  syncer::SyncNotifierHelper notifier_helper_;
+
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncService);
 };