[ModalDialog] Use PropertyModel for all modal dialogs

+ Use PropertyModel for all modal dialogs
+ Remove ModalDialogView.Params
+ Fix cancel on touch outside not being able to cancel on some area
  for app modal dialogs

Bug: 899318
Change-Id: Ib3f9160d57483ade1aa54f1522aa7fe73eaa4212
Reviewed-on: https://chromium-review.googlesource.com/c/1344435
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609877}