Refactor sync-specific parts out of SyncNotifier/SyncNotifierObserver

chrome/browser/sync/glue/chrome_sync_notification_bridge.cc

Index: chrome/browser/sync/glue/chrome_sync_notification_bridge.cc
diff --git a/chrome/browser/sync/glue/chrome_sync_notification_bridge.cc b/chrome/browser/sync/glue/chrome_sync_notification_bridge.cc
index 76b62bf4755e72e2aaa8fe8d45fbeff07700514d..31db8e2da4443d733b4e32e7b0ea16017d908219 100644
--- a/chrome/browser/sync/glue/chrome_sync_notification_bridge.cc
+++ b/chrome/browser/sync/glue/chrome_sync_notification_bridge.cc
@@ -6,10 +6,10 @@
 
 #include "base/bind.h"
 #include "base/location.h"
-#include "base/observer_list.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
+#include "sync/notifier/sync_notifier_helper.h"
 #include "sync/notifier/sync_notifier_observer.h"
 
 using content::BrowserThread;
@@ -26,8 +26,8 @@ class ChromeSyncNotificationBridge::Core
   // All member functions below must be called on the sync task runner.
 
   void UpdateEnabledTypes(syncer::ModelTypeSet enabled_types);
-  void AddObserver(syncer::SyncNotifierObserver* observer);
-  void RemoveObserver(syncer::SyncNotifierObserver* observer);
+  void UpdateRegisteredIds(syncer::SyncNotifierObserver* handler,
+                           const syncer::ObjectIdSet& ids);
 
   void EmitNotification(
       const syncer::ModelTypePayloadMap& payload_map,
@@ -43,7 +43,7 @@ class ChromeSyncNotificationBridge::Core
 
   // Used only on |sync_task_runner_|.
   syncer::ModelTypeSet enabled_types_;
-  ObserverList<syncer::SyncNotifierObserver> observers_;
+  syncer::SyncNotifierHelper helper_;
 };
 
 ChromeSyncNotificationBridge::Core::Core(
@@ -64,16 +64,11 @@ void ChromeSyncNotificationBridge::Core::UpdateEnabledTypes(
   enabled_types_ = types;
 }
 
-void ChromeSyncNotificationBridge::Core::AddObserver(
-    syncer::SyncNotifierObserver* observer) {
+void ChromeSyncNotificationBridge::Core::UpdateRegisteredIds(
+    syncer::SyncNotifierObserver* handler,
+    const syncer::ObjectIdSet& ids) {
   DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
-  observers_.AddObserver(observer);
-}
-
-void ChromeSyncNotificationBridge::Core::RemoveObserver(
-    syncer::SyncNotifierObserver* observer) {
-  DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
-  observers_.RemoveObserver(observer);
+  helper_.UpdateRegisteredIds(handler, ids);
 }
 
 void ChromeSyncNotificationBridge::Core::EmitNotification(
@@ -85,9 +80,9 @@ void ChromeSyncNotificationBridge::Core::EmitNotification(
       syncer::ModelTypePayloadMapFromEnumSet(enabled_types_, std::string()) :
       payload_map;
 
-  FOR_EACH_OBSERVER(
-      syncer::SyncNotifierObserver, observers_,
-      OnIncomingNotification(effective_payload_map, notification_source));
+  helper_.DispatchInvalidationsToHandlers(
+      ModelTypePayloadMapToObjectIdPayloadMap(effective_payload_map),
+      notification_source);
 }
 
 ChromeSyncNotificationBridge::ChromeSyncNotificationBridge(
@@ -111,16 +106,11 @@ void ChromeSyncNotificationBridge::UpdateEnabledTypes(
   core_->UpdateEnabledTypes(types);
 }
 
-void ChromeSyncNotificationBridge::AddObserver(
-    syncer::SyncNotifierObserver* observer) {
-  DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
-  core_->AddObserver(observer);
-}
-
-void ChromeSyncNotificationBridge::RemoveObserver(
-    syncer::SyncNotifierObserver* observer) {
+void ChromeSyncNotificationBridge::UpdateRegisteredIds(
+    syncer::SyncNotifierObserver* handler,
+    const syncer::ObjectIdSet& ids) {
   DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
-  core_->RemoveObserver(observer);
+  core_->UpdateRegisteredIds(handler, ids);
 }
 
 void ChromeSyncNotificationBridge::Observe(