Add second copy request after screen rotation to flatten the layers in animation.

ash/rotator/test/screen_rotation_animator_test_api.cc

Index: ash/rotator/test/screen_rotation_animator_test_api.cc
diff --git a/ash/rotator/test/screen_rotation_animator_test_api.cc b/ash/rotator/test/screen_rotation_animator_test_api.cc
index 0c26e474efb6c8aefc78548e1b730d7a91a62036..0d3d679a61f9aee00942e564b80691bd20921205 100644
--- a/ash/rotator/test/screen_rotation_animator_test_api.cc
+++ b/ash/rotator/test/screen_rotation_animator_test_api.cc
@@ -28,6 +28,10 @@ ScreenRotationAnimatorTestApi::GetLayerAnimators() {
     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;
 }