This CL aims to clean the code in App Class to
handle State, View according to the Model-View-Controller
design pattern.

Bug: v8:10644, v8:10735

Link: https://docs.google.com/presentation/d/1ssCIWKS5TIp_PHZRUx2BfElEz6JFrYzz_Ce1h1g8ZBg/edit?usp=sharing

Change-Id: Ie36d437df0df574f505a4396b26526a82215f237
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2324247
Commit-Queue: Zeynep Cankara <zcankara@google.com>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69218}