Fix lifetime of leveldb::MojoEnv instances.

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 aca402228a57c1f5a54f548f6b8011e49761d141..84003d479c0fc1b18a8b294ce5a62fb8e1378347 100644
--- a/components/leveldb/leveldb_service_impl.h
+++ b/components/leveldb/leveldb_service_impl.h
@@ -12,6 +12,9 @@
 
 namespace leveldb {
 
+class Env;
+class MojoEnv;
+
 // Creates LevelDBDatabases based scoped to a |directory|/|dbname|.
 class LevelDBServiceImpl : public mojom::LevelDBService {
  public:
@@ -23,7 +26,6 @@ class LevelDBServiceImpl : public mojom::LevelDBService {
   ~LevelDBServiceImpl() override;
 
   // Overridden from LevelDBService:
-  void SetEnvironmentName(const std::string& name) override;
   void Open(filesystem::mojom::DirectoryPtr directory,
             const std::string& dbname,
             leveldb::mojom::LevelDBDatabaseAssociatedRequest database,
@@ -41,12 +43,7 @@ class LevelDBServiceImpl : public mojom::LevelDBService {
                const DestroyCallback& callback) override;
 
  private:
-  // 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<LevelDBMojoProxy> thread_;
-
-  std::string environment_name_;
+  MojoEnv* env_;
 
   DISALLOW_COPY_AND_ASSIGN(LevelDBServiceImpl);
 };