Enable mojo localstorage to actually store on disk.

content/browser/leveldb_wrapper_impl.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 "content/browser/leveldb_wrapper_impl.h"
 
 #include "base/bind.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/leveldb/public/cpp/util.h"
@@ skipping 232 matching lines @@
     all.push_back(std::move(kv));
   }
   callback.Run(leveldb::mojom::DatabaseError::OK, std::move(all));
   if (complete_callback.is_valid()) {
     mojom::LevelDBWrapperGetAllCallbackAssociatedPtr complete_ptr;
     complete_ptr.Bind(std::move(complete_callback));
     complete_ptr->Complete(true);
   }
 }
 
+void LevelDBWrapperImpl::Sync(const SyncCallback& callback) {
+  callback.Run();
+}
+
 void LevelDBWrapperImpl::OnConnectionError() {
   if (!bindings_.empty())
     return;
   // If any tasks are waiting for load to complete, delay calling the
   // no_bindings_callback_ until all those tasks have completed.
   if (!on_load_complete_tasks_.empty())
     return;
   delegate_->OnNoBindings();
 }
 
@@ skipping 160 matching lines @@
                               weak_ptr_factory_.GetWeakPtr()));
 }
 
 void LevelDBWrapperImpl::OnCommitComplete(leveldb::mojom::DatabaseError error) {
   --commit_batches_in_flight_;
   StartCommitTimer();
   delegate_->DidCommit(error);
 }
 
 }  // namespace content