Migrate ErrorBar from .js to .tsx

Summary: Migrated the ErrorBar from JS to TS.

Reviewed By: passy

Differential Revision: D16730539

fbshipit-source-id: 3fd8c90f218f7a1d666c3d47380d56868c1cd23f

src/chrome/ErrorBar.tsx

@@ -0,0 +1,33 @@
+/**
+ * Copyright 2018-present Facebook.
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * @format
+ */
+
+import {styled, colors} from 'flipper';
+import React from 'react';
+
+const ErrorBarContainer = styled('div')({
+  backgroundColor: colors.cherry,
+  bottom: 0,
+  color: '#fff',
+  left: 0,
+  lineHeight: '26px',
+  position: 'absolute',
+  right: 0,
+  textAlign: 'center',
+  zIndex: 2,
+});
+
+type Props = {
+  text: string | null | undefined;
+};
+
+export default function ErrorBar(props: Props) {
+  if (props.text == null) {
+    return null;
+  } else {
+    return <ErrorBarContainer>{props.text}</ErrorBarContainer>;
+  }
+}