I believe it would be better to reuse code between WPF and WinRT versions of the Kinect v2 version of the library, using shared projects (and conditional compilation blocks) as shown near the end of this article:
http://mtaulty.com/CommunityServer/blogs/mike_taultys_blog/archive/2014/11/17/shared-projects-common-libraries-on-kinect-for-windows-v2-sdk-bits.aspx
btw, a very nice free extension for Visual Studio to compare/merge code files is Code Compare (you get intellisense etc. while editing/merging stuff)