clean up console

Summary: The console was pretty spammy. This fixes some issues that were logged and changes many log statements to `console.debug` which are not shown by default.

Reviewed By: passy

Differential Revision: D9303011

fbshipit-source-id: 1102f4f8814152a45f155cb43488a515c2d4eee4

src/chrome/WelcomeScreen.js

@@ -103,10 +103,12 @@ export default class WelcomeScreen extends PureComponent<Props, State> {
     isMounted: false,
   };
 
+  timer: ?TimeoutID;
+
   componentDidMount() {
     // waiting sometime before showing the welcome screen to allow Flipper to
     // connect to devices, if there are any
-    setTimeout(
+    this.timer = setTimeout(
       () =>
         this.setState({
           isMounted: true,
@@ -115,6 +117,12 @@ export default class WelcomeScreen extends PureComponent<Props, State> {
     );
   }
 
+  componentWillUnmount() {
+    if (this.timer) {
+      clearTimeout(this.timer);
+    }
+  }
+
   render() {
     return (
       <Container>