Compiler error when building for Android after exporting Oculus assets

I have a Unity project which I'm planning to build both for PC and Android. The project is a VR game. For PC I'm using the Oculus SDK and for mobile I'm using ALPSVR SDK. I was working solely with ALPSVR and everything was working fine on my Android device. However, after I added Oculus assets to the project, I started getting the following error when trying to build the .apk file:

 Assets/OVR/Scripts/OVRManager.cs(401,24): error CS0246: The type or namespace name `OVRVolumeControl' could not be found. Are you missing a using directive or an assembly reference?

1) What might be the reason for this error?

2) Is there a way I can build for Android while keeping the Oculus assets inside the project? Right now, it seems feasible to wrap everything about the gameplay, build for Android, then add the Oculus assets to build for PC. But it would be much more convenient if I could keep the Oculus assets and test for PC during the development phase.