HP Pronq is a web based IDE as a service which is fully functioning when you are offline, with desktop-like performance, ability to connect to git and svn on-premise repositories and the ability to keep your source files solely on your local device in order to protect your privacy in addition to being fully extensible for other developers to enrich its functionality and share it.
Most basic requirements: select changes for review, send request, persist the request in the server, push notification to code reviewer, dedicated view for changes (file tree, highlight added and removed lines, navigation, add inline comments, approve/reject, update code review.
Enhancements: choose the code reviewer, integrate with source control (git or general), support other changes types, approve/reject per change/file and more.