Yury Semikhatsky has been working in the developer tools area (Web Inspector) for a while. In addition to numerous fixes in tracking resources, CSS inspection and related items, he made some very complex contributions including the inspection of cross-domain iframes while preserving the original security model and changing the way the inspector interacts with the host. The latter allowed the embedder to split the inspected page and inspector entities which is a significant step towards remote debugging. In the Chromium port, Yury is the original author and major contributor to the debugger front-end.
Jian Li started his work in WebKit developing V8/Chromium bindings for Web Workers, continuing with adding many features to them, and then fixing multiple issues. More recently, he has made significant contributions to the Drag and Drop implementation and is currently working on the File API (Blob, FileReader, File.urn) and FormData API. He also contributed numerous fixes and features for Chromium port.
Please join me in congratulating Yury and Jian on their reviewer status!