Replace the profile button in the performance bar to a flamegraph
Problem to solve
Today in Performance Bar, click profile button will show
profile of the code used to generate the page, line by line. In the profile view, the numbers in the left panel represent wall time, cpu time, and number of calls (based on rblineprof)
As per https://gitlab.com/gitlab-org/gitlab-ce/issues/62270#note_193793549 and https://gitlab.com/gitlab-org/gitlab-ce/issues/62270#note_194480117, the flamegraph in stackprof is more useful than the line profile in practice.
This issue is to replace the profile button in the performance bar to a flamegraph.
Intended users
Proposal
In the same place where today it invokes rblineprof, replace rblineprof to stackprof, and generate flamegraph.
What does success look like, and how can we measure that?
Be able to show flamegraph of the code which generating the page, when click profile button from Performance Bar