Implemented screen rotation animation experiment.

ash/content/display/screen_orientation_controller_chromeos.cc

Index: ash/content/display/screen_orientation_controller_chromeos.cc
diff --git a/ash/content/display/screen_orientation_controller_chromeos.cc b/ash/content/display/screen_orientation_controller_chromeos.cc
index 1480cfbb9beb06f5c28b38133f5b9d7df2270c64..d8896fbd95dd658da8d7f637f2e9f993152e009f 100644
--- a/ash/content/display/screen_orientation_controller_chromeos.cc
+++ b/ash/content/display/screen_orientation_controller_chromeos.cc
@@ -7,6 +7,7 @@
 #include "ash/ash_switches.h"
 #include "ash/display/display_info.h"
 #include "ash/display/display_manager.h"
+#include "ash/rotator/screen_rotation_animator.h"
 #include "ash/shell.h"
 #include "ash/wm/maximize_mode/maximize_mode_controller.h"
 #include "base/auto_reset.h"
@@ -113,8 +114,8 @@ void ScreenOrientationController::SetDisplayRotation(
   current_rotation_ = rotation;
   base::AutoReset<bool> auto_ignore_display_configuration_updates(
       &ignore_display_configuration_updates_, true);
-  display_manager->SetDisplayRotation(gfx::Display::InternalDisplayId(),
-                                      rotation);
+  ash::ScreenRotationAnimator(gfx::Display::InternalDisplayId())
+      .Rotate(rotation);
 }
 
 void ScreenOrientationController::OnWindowActivated(aura::Window* gained_active,