Looks like Google used Intel's foundry unit to manufacture a custom chip. CNBC received confirmation from the search giant that the Pixel Visual Core, which is found in the new Pixel 2 and Pixel 2 XL smartphones, was built with Intel:
"Google built Pixel Visual Core with Intel," the Google spokesperson wrote in an email to CNBC. "Pixel Visual Core is a custom designed processor from Google, built to serve specific computational photography requirements that could not be met by existing chips."
The Pixel Visual Core is designed to process HDR+ images five times faster and ten times more energy efficient than the smartphone's main Snapdragon 835 SoC. Additionally, the Pixel Visual Core will also boost the performance of certain AI features of apps. At the moment, this core is still deactivated. Google's upcoming Android 8.1 build will activate this feature.