Lazy-load performance bar in frontend
In !20201 (merged) we removed the dynamic code-splitting for the performance bar because it turns out that it needed to be loaded before any axios requests were made so that it could install an interceptor. By including this in the main chunk, we're increasing our bundle size by around 12Kb for a feature only used by GitLab devs for debugging purposes.
We ought to split out the performance bar code such that we include the minimum amount of code to install the request interceptors and then dynamically load the rest. This should be as simple as extracting the code within performance_bar/services/performance_bar_service.js
and writing a lite wrapper to bootstrap the rest.
/cc @smcgivern