Add integraton test for sync backup/rollback.

chrome/browser/sync/profile_sync_service.cc

Index: chrome/browser/sync/profile_sync_service.cc
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index 47aa0f9d97c69e1941f921fb64cfa729ddd9c1a3..a656dbd306fb035e541b364beea16fb8f7618640 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -182,6 +182,7 @@ ProfileSyncService::ProfileSyncService(
       sync_service_url_(kDevServerUrl),
       is_first_time_sync_configure_(false),
       backend_initialized_(false),
+      is_syncing_(false),
       sync_disabled_by_admin_(false),
       is_auth_in_progress_(false),
       signin_(signin_wrapper),
@@ -343,8 +344,10 @@ void ProfileSyncService::TrySyncDatatypePrefRecovery() {
 }
 
 void ProfileSyncService::StartSyncingWithServer() {
-  if (backend_)
+  if (backend_) {
+    is_syncing_ = true;
     backend_->StartSyncingWithServer();
+  }
 }
 
 void ProfileSyncService::RegisterAuthNotifications() {
@@ -827,6 +830,7 @@ void ProfileSyncService::ShutdownImpl(
   expect_sync_configuration_aborted_ = false;
   is_auth_in_progress_ = false;
   backend_initialized_ = false;
+  is_syncing_ = false;
   cached_passphrase_.clear();
   access_token_.clear();
   encryption_pending_ = false;
@@ -1887,6 +1891,7 @@ void ProfileSyncService::ConfigureDataTypeManager() {
     }
   }
 
+  is_syncing_ = false;
   directory_data_type_manager_->Configure(types, reason);
 }