While a software developer may not be directly involved with the testing and quality assurance of the code they develop, who should be familiar with the processes. This will help them code for the requirements of Google. The interviewer uses this operational question to determine the type of quality control systems you have worked with and confirm that your processes are similar to the ones Google uses. Even if your experience isn't an exact match to theirs, you should be able to describe how you would quickly transition to Google's processes.