It depends on if the G2 has a specific sensor dedicated to that function, and if the GPro has that same sensor. Also that function is definitely Framework related so ported may be difficult unless we get the entire Rom or all the necessary files for the port.
Future Phone: LG Google Nexus 5
Current Phones: Samsung Galaxy Note 3 AT&T[Rooted], LG Optimus G Pro AT&T[Liquid Smooth]
Past: LG Optimus G AT&T, LG Google Nexus 4, Samsung Galaxy S3 AT&T, Samsung GS2 AT&T, Sony Xperia ion AT&T, Samsung Infuse AT&T(First Android Phone), All iPhones before that.