Remove KioskNext code from overview_grid.c.

Bug: 977019
Change-Id: Ie6547867532f9883a84713cde0d39b8c40a07fce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1686052
Commit-Queue: Yilkal Abe <yilkal@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#677993}

ash/wm/overview/overview_grid.cc

@@ -8,7 +8,6 @@
 #include <functional>
 #include <utility>
 
-#include "ash/kiosk_next/kiosk_next_shell_controller_impl.h"
 #include "ash/metrics/histogram_macros.h"
 #include "ash/public/cpp/ash_features.h"
 #include "ash/public/cpp/fps_counter.h"
@@ -864,11 +863,6 @@ void OverviewGrid::OnStartingAnimationComplete(bool canceled) {
 }
 
 bool OverviewGrid::ShouldAnimateWallpaper() const {
-  // Kiosk next shell mode will have an opaque background covering the wallpaper
-  // prior to entering overview, so there's no need to animate it.
-  if (Shell::Get()->kiosk_next_shell_controller()->IsEnabled())
-    return false;
-
   // Never animate when doing app dragging or when immediately exiting.
   const auto enter_exit_type = overview_session_->enter_exit_overview_type();
   if (enter_exit_type ==