[ash-md] Remove the number of animators used for the Shelf animations.

ash/BUILD.gn

Index: ash/BUILD.gn
diff --git a/ash/BUILD.gn b/ash/BUILD.gn
index 5549cfea86fce109f34c1d91f60514c053d34bdd..8087847f192fb837bf7a030605fb4a6c2576282d 100644
--- a/ash/BUILD.gn
+++ b/ash/BUILD.gn
@@ -27,6 +27,7 @@ component("ash") {
     "accelerators/magnifier_key_scroller.h",
     "accelerators/spoken_feedback_toggler.cc",
     "accelerators/spoken_feedback_toggler.h",
+    "animation/animation_change_type.h",
     "app_list/app_list_delegate_impl.cc",
     "app_list/app_list_delegate_impl.h",
     "app_list/app_list_presenter_delegate.cc",
@@ -461,8 +462,6 @@ component("ash") {
     "common/wallpaper/wallpaper_widget_controller.h",
     "common/wm/always_on_top_controller.cc",
     "common/wm/always_on_top_controller.h",
-    "common/wm/background_animator.cc",
-    "common/wm/background_animator.h",
     "common/wm/container_finder.cc",
     "common/wm/container_finder.h",
     "common/wm/default_state.cc",