Remove pauser until crbug.com/1237981 is resolved

(cherry picked from commit 9658910)

Bug: 1234555, 1237981
Test: no clear repro step. speculative fix.
Change-Id: Id86055394c2e33eb8b682709a2cc3f25c0d63714
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3082206
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#910053}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3111090
Commit-Queue: Daniel Gagnon <dgagnon@google.com>
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Auto-Submit: Daniel Gagnon <dgagnon@google.com>
Cr-Commit-Position: refs/branch-heads/4515@{#2073}
Cr-Branched-From: 488fc70-refs/heads/master@{#885287}

ash/wm/lock_state_controller.cc

@@ -18,7 +18,6 @@
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/shutdown_reason.h"
-#include "ash/utility/occlusion_tracker_pauser.h"
 #include "ash/wallpaper/wallpaper_controller_impl.h"
 #include "ash/wallpaper/wallpaper_widget_controller.h"
 #include "ash/wm/session_state_animator.h"
@@ -248,8 +247,6 @@ void LockStateController::OnLockStateChanged(bool locked) {
 
   system_is_locked_ = locked;
 
-  Shell::Get()->occlusion_tracker_pauser()->PauseUntilAnimationsEnd();
-
   if (locked) {
     StartPostLockAnimation();