Originally Posted by agentdr8
Very unlikely, as there are other FB sync apps out there.
you do realize that despite such a prospect, those developers who actually tried doing such a thing were suckered into Facebook's payroll and the apps were abandoned (Mathhias Roth and HaxSync are a perfect example). The apps that currently exist on the Play Store do NOT allow Contact Sync, and the reason why is very simple: it requires a modification of the ContactsProvider.apk in /system/app (or /system/priv-app on 4.4.x) and modification of system files requires root access and an insecure kernel (in my case, as despite root access on my HTC One M8, I can't change a single system file).
The only reason most individuals have no worry is because OEMs like Samsung and HTC modify it themselves. This is an AOSP/Untampered/Skinless Android issue and like @RandomPooka
said earlier, CyanogenMod devs refuse to do this by principle, as Facebook is indeed a bunch of code savages that do everything in their power to retain control of their code. They make Apple and Microsoft's closed-source OS framework look tame in comparison. Those boneheads need to be taught a lesson, and a note to all who fork agentdr8's code - DO NOT BE SUCKERED INTO FACEBOOK'S PAYROLL. If Cyanogen, Inc. can turn down an offer from Google, you should have the same degree of self-control and nobility to say NO.