Chainfire has rooted the Pixel. Check on XDA. Here is the readme.txt file:
***** The short guide *****
*BOOT* (do not flash!) the supplied image, and wait a few minutes:
fastboot boot boot-to-root.img
***** The long guide *****
Before you root your device, you need to unlock your bootloader, if you haven't done so yet.
If you are using a Verizon device, you need a special tool for that. Go find that first.
- Boot into Android
- Enable developer options
--- Settings -> About phone -> Build number: tap 7 times
- Enable OEM unlocking
--- Settings -> Developer Options -> OEM unlocking
- Go into bootloader mode
--- Turn off device
--- Hold volume down and power
- Run "fastboot flashing unlock" and follow the on-screen instructions
--- This will wipe your device
To root your device:
- Go into bootloader mode, if not there already
--- Turn off device
--- Hold volume down and power
- Run "fastboot boot boot-to-root.img"
--- Wait for a few minutes. The device will reboot at least twice
- You should be rooted once Android is fully booted up
*****
Enjoy!
- Chainfire