Flip the flag to enable smooth screen rotation by default.

ash/rotator/test/screen_rotation_animator_test_api.cc

 // Copyright 2017 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.
 
 #include "ash/rotator/test/screen_rotation_animator_test_api.h"
 
 #include "ash/rotator/screen_rotation_animator.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_tree_owner.h"
 
 namespace ash {
 namespace test {
 
 ScreenRotationAnimatorTestApi::ScreenRotationAnimatorTestApi(
     ScreenRotationAnimator* animator)
     : ui::test::MultiLayerAnimatorTestController(this), animator_(animator) {}
 
 ScreenRotationAnimatorTestApi::~ScreenRotationAnimatorTestApi() {}
 
 void ScreenRotationAnimatorTestApi::DisableAnimationTimers() {
   animator_->set_disable_animation_timers_for_test(true);
 }
 
+void ScreenRotationAnimatorTestApi::SetEnableAnimation(bool enable) {
+  animator_->set_enable_animation_for_test(enable);
+}
+
 std::vector<ui::LayerAnimator*>
 ScreenRotationAnimatorTestApi::GetLayerAnimators() {
   std::vector<ui::LayerAnimator*> animators;
   if (animator_->old_layer_tree_owner_) {
     animators.insert(animators.end(),
                      animator_->old_layer_tree_owner_->root()->GetAnimator());
   }
   if (animator_->new_layer_tree_owner_) {
     animators.insert(animators.end(),
                      animator_->new_layer_tree_owner_->root()->GetAnimator());
   }
   return animators;
 }
 
 }  // namespace test
 }  // namespace ash