[Sync] Switch ModelTypeStore* from blocking pool to post_task.h

components/sync/model_impl/model_type_store_impl.h

 // Copyright 2015 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.
 
 #ifndef COMPONENTS_SYNC_MODEL_IMPL_MODEL_TYPE_STORE_IMPL_H_
 #define COMPONENTS_SYNC_MODEL_IMPL_MODEL_TYPE_STORE_IMPL_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 12 matching lines @@
 
 class ModelTypeStoreBackend;
 
 // ModelTypeStoreImpl handles details of store initialization, threading and
 // leveldb key formatting. Actual leveldb IO calls are performed by
 // ModelTypeStoreBackend.
 class ModelTypeStoreImpl : public ModelTypeStore, public base::NonThreadSafe {
  public:
   ~ModelTypeStoreImpl() override;
 
-  static void CreateStore(
-      ModelType type,
-      const std::string& path,
-      scoped_refptr<base::SequencedTaskRunner> blocking_task_runner,
-      const InitCallback& callback);
+  static void CreateStore(ModelType type,
+                          const std::string& path,
+                          const InitCallback& callback);
   static void CreateInMemoryStoreForTest(ModelType type,
                                          const InitCallback& callback);
 
   // ModelTypeStore implementation.
   void ReadData(const IdList& id_list,
                 const ReadDataCallback& callback) override;
   void ReadAllData(const ReadAllDataCallback& callback) override;
   void ReadAllMetadata(const ReadMetadataCallback& callback) override;
   std::unique_ptr<WriteBatch> CreateWriteBatch() override;
   void CommitWriteBatch(std::unique_ptr<WriteBatch> write_batch,
@@ skipping 75 matching lines @@
 
   // Key for this type's global metadata record.
   const std::string global_metadata_key_;
 
   base::WeakPtrFactory<ModelTypeStoreImpl> weak_ptr_factory_;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_MODEL_IMPL_MODEL_TYPE_STORE_IMPL_H_