Merge branch '351769-drop-feature-flag' into 'master'

Remove track_application_boot_time feature flag

See merge request gitlab-org/gitlab!80366

config/feature_flags/development/track_application_boot_time.yml

----
-name: track_application_boot_time
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/79139
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/351769
-milestone: '14.8'
-type: development
-group: group::memory
-default_enabled: true

lib/gitlab/metrics/boot_time_tracker.rb

@@ -15,7 +15,7 @@ module Gitlab
         return if @startup_time
 
         runtime = Gitlab::Runtime.safe_identify
-        return unless SUPPORTED_RUNTIMES.include?(runtime) && Feature.enabled?(:track_application_boot_time, default_enabled: :yaml)
+        return unless SUPPORTED_RUNTIMES.include?(runtime)
 
         @startup_time = Gitlab::Metrics::System.process_runtime_elapsed_seconds
 

spec/lib/gitlab/metrics/boot_time_tracker_spec.rb

 # frozen_string_literal: true
 
-require 'spec_helper'
+require 'fast_spec_helper'
 
 RSpec.describe Gitlab::Metrics::BootTimeTracker do
   let(:logger) { double('logger') }
@@ -74,20 +74,6 @@ RSpec.describe Gitlab::Metrics::BootTimeTracker do
         tracker.track_boot_time!(logger: logger)
       end
     end
-
-    # TODO: When https://gitlab.com/gitlab-org/gitlab/-/issues/351769 is closed,
-    #       revert to using fast_spec_helper again.
-    context 'when feature flag is off' do
-      it 'does nothing' do
-        stub_feature_flags(track_application_boot_time: false)
-
-        expect(Gitlab::Metrics::System).not_to receive(:process_runtime_elapsed_seconds)
-        expect(logger).not_to receive(:info)
-        expect(gauge).not_to receive(:set)
-
-        tracker.track_boot_time!(logger: logger)
-      end
-    end
   end
 
   describe '#startup_time' do