Make performance bar enabled checks consistent

Previously, we called the `peek_enabled?` method like so:

    prepend_before_action :set_peek_request_id, if: :peek_enabled?

Now we don't have a `set_peek_request_id` method, so we don't need that
line. However, the `peek_enabled?` part had a side-effect: it would also
populate the request store cache for whether the performance bar was
enabled for the current request or not.

This commit makes that side-effect explicit, and replaces all uses of
`peek_enabled?` with the more explicit
`Gitlab::PerformanceBar.enabled_for_request?`. There is one spec that
still sets `SafeRequestStore[:peek_enabled]` directly, because it is
contrasting behaviour with and without a request store enabled.

The upshot is:

1. We still set the value in one place. We make it more explicit that
   that's what we're doing.
2. Reading that value uses a consistent method so it's easier to find in
   future.

1 files changed, 2 insertions, 6 deletions

diff --git a/lib/gitlab/rugged_instrumentation.rb b/lib/gitlab/rugged_instrumentation.rb
index 8bb8c547ae1..c2b55431547 100644
--- a/lib/gitlab/rugged_instrumentation.rb
+++ b/lib/gitlab/rugged_instrumentation.rb
@@ -27,19 +27,15 @@ module Gitlab
       SafeRequestStore.active?
     end
 
-    def self.peek_enabled?
-      SafeRequestStore[:peek_enabled]
-    end
-
     def self.add_call_details(details)
-      return unless peek_enabled?
+      return unless Gitlab::PerformanceBar.enabled_for_request?
 
       Gitlab::SafeRequestStore[:rugged_call_details] ||= []
       Gitlab::SafeRequestStore[:rugged_call_details] << details
     end
 
     def self.list_call_details
-      return [] unless peek_enabled?
+      return [] unless Gitlab::PerformanceBar.enabled_for_request?
 
       Gitlab::SafeRequestStore[:rugged_call_details] || []
     end