Glad to see google open sourced this. I also implemented code search in my open source project OneDev (https://github.com/theonedev/onedev). To try it, please visit https://code.onedev.io/projects/android-framework-base/. Press "t" for quick symbol search, and "v" for advanced search with regular expression support.

You may also hover mouse over a symbol to find its declaration and occurrences.