Add screen rotation animator lock.

ash/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//ui/base/ui_features.gni")
 
 # Historical note: Ash shipped on Windows for a couple years to support
@@ skipping 218 matching lines @@
     "new_window_controller.h",
     "palette_delegate.h",
     "root_window_controller.cc",
     "root_window_controller.h",
     "root_window_settings.cc",
     "root_window_settings.h",
     "rotator/screen_rotation_animation.cc",
     "rotator/screen_rotation_animation.h",
     "rotator/screen_rotation_animator.cc",
     "rotator/screen_rotation_animator.h",
+    "rotator/screen_rotation_animator_lock.cc",
+    "rotator/screen_rotation_animator_lock.h",
     "rotator/screen_rotation_animator_observer.h",
     "rotator/window_rotation.cc",
     "rotator/window_rotation.h",
     "scoped_root_window_for_new_windows.cc",
     "scoped_root_window_for_new_windows.h",
     "screen_util.cc",
     "screen_util.h",
     "screenshot_delegate.h",
     "session/session_controller.cc",
     "session/session_controller.h",
@@ skipping 1243 matching lines @@
     "//content/public/app:both",
     "//device/bluetooth",
   ]
 
   data_deps = [
     "//ash/strings:ash_test_strings",
     "//ash/resources:ash_test_resources_with_content_100_percent",
     "//ash/resources:ash_test_resources_200_percent",
   ]
 }