Although Nexus 6 is official now but there are few Specs which Google planned for its Nexus 6 but these specs didn't make to assembly. As we already discussed Google coded tap to wake for this year flagship Nexus 6 but pulled out before releasing the device.
Nexus 6 users can re enable this feature if their device is rooted. Now latest Android Source code revealed suggesting that Google Nexus 6 was also featuring finger print scanner but was also removed like tap to wake feature.
Source code further suggests Google is still working on official Android API for fingerprint scanner. In late August Google removed the finger print scanner from Shamu, this order was implied on those prototypes which were from validity sensors. Last year, this company was acquired by Synaptics. Fingerprint scanner from this company didn't require big bezels like an iPhone.
There are also reports of Google compels to AOSP which was to pelt the fingerprint scanner code in latest Android 5.0 until Google release a new API. From look of things it seems Google fingerprint API will be of swipe style similar to Samsung fingerprint scanner.
Code also suggested that Google fingerprint will allow users to authenticate reliable apps with their fingerprint. These features are pretty nice, but unfortunately didn't made in time for this year flagship Nexus 6. Nexus fans can expect this feature next year in Android 5.1 API.
source: Ars Technica