Steps to reproduce :

- import the texture attached
- in the inspector select Sprite and Single and apply
- drag the sprite to the scene view and press play
- select the sprite and switch to Manual in the Inspector
- open the Sprite editor, set the slice to Automatic
- press Slice and notice the warning in the console

The referenced script on this Behaviour is missing!
UnityEditor.SpriteEditorWindow:DoAutomaticSlicing(Int32, Int32, AutoSlicingMethod)
UnityEditorInternal.SpriteEditorMenu:DoAutomaticSlicing()
UnityEditorInternal.SpriteEditorMenu:DoSlicing()
UnityEditorInternal.SpriteEditorMenu:OnGUI()
UnityEditor.HostView:OnGUI()