In order to assure the quality of software, early detection of defects is highly recommended. Code review is one of effective way for such early detection of defects in software. Code review activities must contain various useful insights for software quality. However, especially in open source software developments, records of code review merely exist. In this study, we try to analyze a code review repository of an open source software, Chromium, which adopts a code review tool in its development. Before analyzing the code review data, we address 7 research questions. We can find interesting answers for these questions by repositories mining.