Merge 68891 - [Sync] Fixed sync crash regression in ServerNotifierThread

chrome/browser/sync/notifier/server_notifier_thread.cc

Index: chrome/browser/sync/notifier/server_notifier_thread.cc
diff --git a/chrome/browser/sync/notifier/server_notifier_thread.cc b/chrome/browser/sync/notifier/server_notifier_thread.cc
index 24a1c47526cbe194c81891605223e824cfedfe85..f16587ff97a3863ee0c85de4794d41a156fb9718 100644
--- a/chrome/browser/sync/notifier/server_notifier_thread.cc
+++ b/chrome/browser/sync/notifier/server_notifier_thread.cc
@@ -123,7 +123,9 @@ void ServerNotifierThread::DoListenForUpdates() {
 
 void ServerNotifierThread::RegisterTypesAndSignalSubscribed() {
   DCHECK_EQ(MessageLoop::current(), worker_message_loop());
-  DCHECK(chrome_invalidation_client_.get());
+  if (!chrome_invalidation_client_.get()) {
+    return;
+  }
   chrome_invalidation_client_->RegisterTypes();
   observers_->Notify(&Observer::OnSubscriptionStateChange, true);
 }