`UnityEditor.EditorUtility' does not contain a definition for `GetMiniThumbnail'

I got the following errors with Untiy 4.0f7

error CS0117: `UnityEditor.EditorUtility' does not contain a definition for `GetMiniThumbnail'

error CS0117: `UnityEditor.EditorUtility' does not contain a definition for `ResetGameObjectToPrefabState'

error CS0117: `UnityEditor.ReplacePrefabOptions' does not contain a definition for `UseLastUploadedPrefabRoot'

I've already have Unity3.5.6f4 and installed Untiy 4.0f7. ( which means both of the version are on my windows machine)

All the above methods are shown on the document but Unity didn't resolved that methods. 

What's wrong?

Just figured it out. 

Replacing the following solved the problem. 

1) Replaced EditorUtility.GetMiniThumbnails() to AssetPreview.GetMiniThumbnail()
2) Replaced EditorUtility.ReplacePrefab() to PrefabUtility.ReplacePrefab()
3) Replaced EditorUtility.ResetGameObjectToPrefabState() to PrefabUtility.ResetToPrefabState();

By the way, I'm not sure just replace 'ReplacePrefabOptions.UseLastUploadedPrefabRoot' option to 'ReplacePrefabOptions.Default' which is passed to PrefabUtility.ReplacePrefab() method. 

ReplacePrefabOptions.UseLastUploadedPrefabRoot seems to be deprecated. 

Thank you. 

-Kim