ash: Tune shutdown animation time to 1.5s for convertible devices

ash/wm/session_state_animator.cc

Index: ash/wm/session_state_animator.cc
diff --git a/ash/wm/session_state_animator.cc b/ash/wm/session_state_animator.cc
index 73ddd43b8764bf4e89cd3240ea55f351922fa166..db620bb8abb3ca12091b3ff5cd2f44a66b1db2eb 100644
--- a/ash/wm/session_state_animator.cc
+++ b/ash/wm/session_state_animator.cc
@@ -95,7 +95,7 @@ base::TimeDelta SessionStateAnimator::GetDuration(
     case ANIMATION_SPEED_UNDO_MOVE_WINDOWS:
       return base::TimeDelta::FromMilliseconds(350);
     case ANIMATION_SPEED_SHUTDOWN:
-      return IsTouchViewEnabled() ? base::TimeDelta::FromMilliseconds(2500)
+      return IsTouchViewEnabled() ? base::TimeDelta::FromMilliseconds(1500)
                                   : base::TimeDelta::FromMilliseconds(1000);
     case ANIMATION_SPEED_REVERT_SHUTDOWN:
       return base::TimeDelta::FromMilliseconds(500);