mojo leveldb: Remove the created file thread.

components/leveldb/leveldb_service_impl.h

Index: components/leveldb/leveldb_service_impl.h
diff --git a/components/leveldb/leveldb_service_impl.h b/components/leveldb/leveldb_service_impl.h
index b5f90006813eded6b2cba750a6cc9f1a5572677c..c234fd5683dd49af1dfb98bc179eeaf95178a2cd 100644
--- a/components/leveldb/leveldb_service_impl.h
+++ b/components/leveldb/leveldb_service_impl.h
@@ -6,7 +6,7 @@
 #define COMPONENTS_LEVELDB_LEVELDB_SERVICE_IMPL_H_
 
 #include "base/memory/ref_counted.h"
-#include "components/leveldb/leveldb_file_thread.h"
+#include "components/leveldb/leveldb_mojo_proxy.h"
 #include "components/leveldb/public/interfaces/leveldb.mojom.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 
@@ -15,7 +15,7 @@ namespace leveldb {
 // Creates LevelDBDatabases based scoped to a |directory|/|dbname|.
 class LevelDBServiceImpl : public LevelDBService {
  public:
-  LevelDBServiceImpl();
+  LevelDBServiceImpl(scoped_refptr<base::SingleThreadTaskRunner> task_runner);
   ~LevelDBServiceImpl() override;
 
   // Overridden from LevelDBService:
@@ -30,7 +30,7 @@ class LevelDBServiceImpl : public LevelDBService {
   // Thread to own the mojo message pipe. Because leveldb spawns multiple
   // threads that want to call file stuff, we create a dedicated thread to send
   // and receive mojo message calls.
-  scoped_refptr<LevelDBFileThread> thread_;
+  scoped_refptr<LevelDBMojoProxy> thread_;
 
   DISALLOW_COPY_AND_ASSIGN(LevelDBServiceImpl);
 };