Revert of Quit the message loop by default in ShellConnectionLost when ApplicationRunner is used

components/filesystem/file_system_app.h

Index: components/filesystem/file_system_app.h
diff --git a/components/filesystem/file_system_app.h b/components/filesystem/file_system_app.h
index 86aee79598e296d402a8139605c3659cbf7f54f5..1eb65c3e7ed148d402d3f8f9044818ad54c3f8a3 100644
--- a/components/filesystem/file_system_app.h
+++ b/components/filesystem/file_system_app.h
@@ -34,6 +34,8 @@
   void Initialize(mojo::Connector* connector, const mojo::Identity& identity,
                   uint32_t id) override;
   bool AcceptConnection(mojo::Connection* connection) override;
+  void ShellConnectionLost() override;
+
   // |InterfaceFactory<Files>| implementation:
   void Create(mojo::Connection* connection,
               mojo::InterfaceRequest<FileSystem> request) override;