renderer: showing progress on slow runs

src/components/dialogs/ShotPrefetchDialog.jsx

@@ -0,0 +1,21 @@
+import React from 'react';
+
+type Props = {
+  renderer: {
+    info: String,
+    progress: Number,
+  }
+}
+
+export const ShotPrefetchDialog = ({ renderer: { info, progress }}: Props) => (
+  <div className="control-dialog control-dialog-small">
+    <div className="helper helper-prefetch">
+      <div className="dialog-prefetch-stage">{info}</div>
+      <div className="dialog-prefetch-progress">
+        <div className="progress">
+          <div className="bar" style={{ width: `${progress * 100}%` }} />
+        </div>
+      </div>
+    </div>
+  </div>
+);