- Display spinner properly again
- Defer loadding additional App and subsequent modules
- Preload file reader module and template

Change-Id: Ifc81a93864d61c282db90df25f93dc0eefef4373
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2494925
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70730}