Add shutdown notification and service refs to SyncServiceObserver.

components/browser_sync/profile_sync_service.cc

Index: components/browser_sync/profile_sync_service.cc
diff --git a/components/browser_sync/profile_sync_service.cc b/components/browser_sync/profile_sync_service.cc
index d95fccdcf275cf30c22f545529571cfd7cd14f2b..b941c6d38f2af8d0e02625d99c050ccf81a21388 100644
--- a/components/browser_sync/profile_sync_service.cc
+++ b/components/browser_sync/profile_sync_service.cc
@@ -715,6 +715,7 @@ void ProfileSyncService::Shutdown() {
   UnregisterAuthNotifications();
 
   ShutdownImpl(syncer::BROWSER_SHUTDOWN);
+  NotifyShutdown();
   if (sync_error_controller_) {
     // Destroy the SyncErrorController when the service shuts down for good.
     RemoveObserver(sync_error_controller_.get());
@@ -841,17 +842,22 @@ void ProfileSyncService::UpdateLastSyncedTime() {
 
 void ProfileSyncService::NotifyObservers() {
   for (auto& observer : observers_)
-    observer.OnStateChanged();
+    observer.OnStateChanged(this);
 }
 
 void ProfileSyncService::NotifySyncCycleCompleted() {
   for (auto& observer : observers_)
-    observer.OnSyncCycleCompleted();
+    observer.OnSyncCycleCompleted(this);
 }
 
 void ProfileSyncService::NotifyForeignSessionUpdated() {
   for (auto& observer : observers_)
-    observer.OnForeignSessionUpdated();
+    observer.OnForeignSessionUpdated(this);
+}
+
+void ProfileSyncService::NotifyShutdown() {
+  for (auto& observer : observers_)
+    observer.OnSyncShutdown(this);
 }
 
 void ProfileSyncService::ClearStaleErrors() {
@@ -1373,7 +1379,7 @@ void ProfileSyncService::OnConfigureDone(
 
   // Notify listeners that configuration is done.
   for (auto& observer : observers_)
-    observer.OnSyncConfigurationCompleted();
+    observer.OnSyncConfigurationCompleted(this);
 
   DVLOG(1) << "PSS OnConfigureDone called with status: " << configure_status_;
   // The possible status values: