mojo leveldb: Add support to use in memory database.

components/leveldb/leveldb_database_impl.h

 // 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.
 
 #ifndef COMPONENTS_LEVELDB_LEVELDB_DATABASE_IMPL_H_
 #define COMPONENTS_LEVELDB_LEVELDB_DATABASE_IMPL_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "components/leveldb/public/interfaces/leveldb.mojom.h"
 #include "mojo/public/cpp/bindings/interface_request.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
 #include "third_party/leveldatabase/src/include/leveldb/db.h"
 
 namespace leveldb {
 
 class MojoEnv;
 
 // The backing to a database object that we pass to our called.
 class LevelDBDatabaseImpl : public LevelDBDatabase {
  public:
   LevelDBDatabaseImpl(leveldb::LevelDBDatabaseRequest request,
-                      scoped_ptr<MojoEnv> environment,
+                      scoped_ptr<leveldb::Env> environment,
                       scoped_ptr<leveldb::DB> db);
   ~LevelDBDatabaseImpl() override;
 
   // Overridden from LevelDBDatabase:
   void Put(mojo::Array<uint8_t> key,
            mojo::Array<uint8_t> value,
            const PutCallback& callback) override;
   void Delete(mojo::Array<uint8_t> key,
               const DeleteCallback& callback) override;
   void Write(mojo::Array<BatchedOperationPtr> operations,
              const WriteCallback& callback) override;
   void Get(mojo::Array<uint8_t> key, const GetCallback& callback) override;
   void GetSnapshot(const GetSnapshotCallback& callback) override;
   void ReleaseSnapshot(uint64_t snapshot_id) override;
   void GetFromSnapshot(uint64_t snapshot_id,
                        mojo::Array<uint8_t> key,
                        const GetCallback& callback) override;
 
  private:
   mojo::StrongBinding<LevelDBDatabase> binding_;
-  scoped_ptr<MojoEnv> environment_;
+  scoped_ptr<leveldb::Env> environment_;
   scoped_ptr<leveldb::DB> db_;
 
   std::map<uint64_t, const Snapshot*> snapshot_map_;
 
   // TODO(erg): If we have an existing iterator which depends on a snapshot,
   // and delete the snapshot from the client side, that shouldn't delete the
   // snapshot maybe? At worse it's a DDoS if there's multiple users of the
   // system, but this maybe should be fixed...
 
   std::map<uint64_t, Iterator*> iterator_map_;
 
   DISALLOW_COPY_AND_ASSIGN(LevelDBDatabaseImpl);
 };
 
 }  // namespace leveldb
 
 #endif  // COMPONENTS_LEVELDB_LEVELDB_DATABASE_IMPL_H_