cros: Move some *View classes into *Handler files

Also eliminate AppLaunchSplashScreenView::Delegate

Bug: 928555
Change-Id: I056c5fa6efb94bb59c45cbaf8e4344588dd97230
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1564935
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Commit-Queue: Jacob Dufault <jdufault@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652284}
15 files changed