Host and port as function args

Summary:
^

Before this change, the client assumed the host and port came from location.host which is fine on the browser.

In all other cases, that object/properties may be undefined.

As such, add host and port as function args and use that instead.

Reviewed By: passy

Differential Revision: D36440423

fbshipit-source-id: 5f931f1d610d583db6a2e549e1213585f0d03dee

desktop/flipper-ui-browser/src/index.tsx

@@ -28,6 +28,8 @@ async function start() {
   setLoggerInstance(logger);
 
   const flipperServer = await createFlipperServer(
+    location.hostname,
+    parseInt(location.port, 10),
     (state: FlipperServerState) => {
       switch (state) {
         case FlipperServerState.CONNECTING: