Microsoft is still interested in bringing Xbox 360 games to the Xbox One.
During a developer conference Microsoft partner development lead Frank Savage was asked if there are "plans for an Xbox 360 emulator on Xbox One." Savage responded by saying "there are, but we’re not done thinking them through yet, unfortunately. It turns out to be hard to emulate the PowerPC stuff on the X86 stuff. So there’s nothing to announce, but I would love to see it myself."
While this may mean that Xbox 360 games will be available for download on Xbox One someday, there's nothing to confirm that old Xbox 360 discs will work in the Xbox One.
Sony used the PlayStation 3 to emulate both PlayStation 2 and PlayStation 1 games. Unfortunately, PlayStation 2 and 1 discs weren't compatible with the PlayStation 3 (except the first model released).
If you're looking for a new fix on Xbox One or 360 be sure to check out the exclusive Titanfall. Be sure to check back to CGM as more information arises.