Stewart Google Pixels are manufactured by Foxconn. Foxconn is a Taiwanese company, but its key assembly plants for Pixels are located in China, Vietnam, and Taiwan. And a majority of Foxconn's factories, and employees (e.g. one factory employs over 200,000 workers out of about 1.3 million worldwide) are located in China. So, statistically, it is reasonable to expect that a significant percentage of Pixels will be manufactured in China.
Foxconn in China manufactures for Apple (iPhones and iPads), HP, Nintendo, Microsoft, Google, and Amazon.
They do this despite documented supply chain risk of manufacture in China. Cost is a key commercial driver of that. Apple, for one, has pushed back on reshoring manufacture to the US, due to the significant likely increase (doubling or more) in purchase cost - to Americans - for iPhones.
Motorola manufacturing in China will therefore not automatically mean that their products will be deficient, security wise, compared with Pixels. It means they will need to appropriately manage that risk - by quality control and other means - just as other clients of Foxconn do.