Cho, Yongjoon 78d635d39a Fix DebugEngine and add test (#38556) ...

```
'DebugEngine' only refers to a type, but is being used as a value here.ts(2693)
```

```ts
const debug = process.env.NODE_ENV === "production" ? undefined : new DebugEngine();
```

2019-09-25 13:28:46 -07:00

..

index.d.ts

…

styletron-react-tests.tsx

…

tsconfig.json

…

tslint.json

…