[sync] Add constexpr to EnumSet

components/sync/driver/glue/sync_backend_host_impl_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/sync/driver/glue/sync_backend_host_impl.h"
 
 #include <cstddef>
 #include <utility>
 
 #include "base/files/file_util.h"
@@ skipping 330 matching lines @@
   EXPECT_EQ(enabled_types_, fake_manager_->InitialSyncEndedTypes());
   EXPECT_TRUE(
       fake_manager_->GetTypesWithEmptyProgressMarkerToken(enabled_types_)
           .Empty());
 }
 
 // Test the restart after setting up sync scenario. No enabled types should be
 // downloaded or cleaned.
 TEST_F(SyncEngineTest, Restart) {
   sync_prefs_->SetFirstSetupComplete();
-  ModelTypeSet all_but_nigori = enabled_types_;
   fake_manager_factory_->set_progress_marker_types(enabled_types_);
   fake_manager_factory_->set_initial_sync_ended_types(enabled_types_);
   InitializeBackend(true);
   EXPECT_TRUE(fake_manager_->GetAndResetDownloadedTypes().Empty());
   EXPECT_TRUE(
       Intersection(fake_manager_->GetAndResetPurgedTypes(), enabled_types_)
           .Empty());
   EXPECT_EQ(enabled_types_, fake_manager_->InitialSyncEndedTypes());
   EXPECT_TRUE(
       fake_manager_->GetTypesWithEmptyProgressMarkerToken(enabled_types_)
@@ skipping 454 matching lines @@
   backend_->StopSyncingForShutdown();
   // Verify that call to DeactivateNonBlockingDataType doesn't assert.
   backend_->DeactivateNonBlockingDataType(AUTOFILL);
   backend_->Shutdown(STOP_SYNC);
   backend_.reset();
 }
 
 }  // namespace
 
 }  // namespace syncer