Why can't I use MoviePlayer in runtime

when i just include “Runtime/MoviePlayer/Public/MoviePlayer.h”,and did not white any code of this,the visual studio tell me ‘FLoadingScreenAttributes’ uses undefined struct ‘MOVIEPLAYER_API’.
My ue4 version is 4.2.

in this topics:

Duncan Dam’s answer and code help me to make it work.
a important thing is add “MoviePlayer” to yourproject.build.cs like this:
PrivateDependencyModuleNames.AddRange(new string[] { “Slate”, “SlateCore” , “MoviePlayer”});

then you can include “Runtime/MoviePlayer/Public/MoviePlayer.h” and use it.

using this fix does not work in ue4 4.2.5