Avoid import-time side effects for application

Summary:
`INITIAL_STATE` is defined at import-time and relies on `remote.getCurrentWindow()`, which means that any import from the `flipper` module will require a display server + electron running.

Happy to take alternative suggestions to make this look a bit less intrusive.

Reviewed By: danielbuechele

Differential Revision: D10507539

fbshipit-source-id: 62b6bff0b4fd40638e54328613de4d3821b69dd6

src/reducers/application.js

@@ -29,19 +29,17 @@ export type Action = {
   payload?: boolean,
 };
 
-const INITIAL_STATE: State = {
+const initialState: () => State = () => ({
   leftSidebarVisible: true,
   rightSidebarVisible: true,
   rightSidebarAvailable: false,
   bugDialogVisible: false,
   windowIsFocused: remote.getCurrentWindow().isFocused(),
   pluginManagerVisible: false,
-};
+});
 
-export default function reducer(
+export default function reducer(state: State, action: Action): State {
-  state: State = INITIAL_STATE,
+  state = state || initialState();
-  action: Action,
-): State {
   const {payload, type} = action;
   const newValue = typeof payload === 'undefined' ? !state[type] : payload;