Profiling with the Built-in Gecko Profiler and Local Symbols on Windows

If you would like to use the built-in Gecko Profiler with a local build of Firefox for Windows, you will need to point the profiler to a local Snappy Symbolication Server instead of the official Mozilla symbolication server. The server will host the local Firefox symbols for the profiler and it will fetch any symbols not available locally from the official Mozilla symbolication server (e.g. symbols for Windows DLLs and plugin DLLs).

Instructions:
https://developer.mozilla.org/en/Performance/Profiling_with_the_Built-in_Profiler_and_Local_Symbols_on_Windows