[Sync] USS: Filter out tombstones for initial sync.

components/sync/engine_impl/uss_migrator.cc

 // Copyright 2016 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/engine_impl/uss_migrator.h"
 
 #include <algorithm>
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 85 matching lines @@
     for (; i < batch_limit; i++) {
       auto entity = base::MakeUnique<sync_pb::SyncEntity>();
       if (!ExtractSyncEntity(&trans, child_ids[i], entity.get())) {
         LOG(ERROR) << "Failed to fetch child node for "
                    << ModelTypeToString(type);
         // Inform the worker so it can clear any partial data and trigger a
         // fallback initial GetUpdates.
         worker->AbortMigration();
         return false;
       }
-      entity_ptrs.push_back(entity.get());
-      entities.push_back(std::move(entity));
+      // Ignore tombstones; they are not included for initial GetUpdates.
+      if (!entity->deleted()) {
+        entity_ptrs.push_back(entity.get());
+        entities.push_back(std::move(entity));
+      }
     }
 
     worker->ProcessGetUpdatesResponse(progress, context, entity_ptrs, nullptr);
   }
 
   worker->PassiveApplyUpdates(nullptr);
   return true;
 }
 
 }  // namespace syncer