Port Processer api refactor from CE

ee/lib/ee/gitlab/metrics_dashboard/processor.rb

@@ -4,8 +4,8 @@ module EE
   module Gitlab
     module MetricsDashboard
       module Processor
-        def stages
-          @stages ||= super + [Stages::AlertsInserter]
+        def sequence
+          super + [Stages::AlertsInserter]
         end
       end
     end

ee/lib/ee/gitlab/metrics_dashboard/stages/alerts_inserter.rb

@@ -7,10 +7,10 @@ module EE
     module MetricsDashboard
       module Stages
         class AlertsInserter < ::Gitlab::MetricsDashboard::Stages::BaseStage
-          def transform!
+          def transform!(dashboard)
             return if metrics_with_alerts.empty?
 
-            for_metrics do |metric|
+            for_metrics(dashboard) do |metric|
               next unless metrics_with_alerts.include?(metric[:metric_id])
 
               metric[:alert_path] = alert_path(metric[:metric_id], project, environment)

ee/spec/lib/ee/gitlab/metrics_dashboard/processor_spec.rb

@@ -7,19 +7,19 @@ describe Gitlab::MetricsDashboard::Processor do
   let(:environment) { create(:environment, project: project) }
   let(:dashboard_yml) { YAML.load_file('spec/fixtures/lib/gitlab/metrics_dashboard/sample_dashboard.yml') }
 
-  describe 'stages' do
+  describe 'sequence' do
     let(:environment) { build(:environment) }
-    let(:process_params) { [dashboard_yml, project, environment] }
-    let(:stages) { described_class.new(*process_params).stages }
+    let(:process_params) { [project, environment] }
+    let(:sequence) { described_class.new(*process_params).sequence }
 
     it 'includes the alerts processing stage' do
-      expect(stages.length).to eq(4)
+      expect(sequence.length).to eq(4)
     end
   end
 
   describe 'process' do
-    let(:process_params) { [dashboard_yml, project, environment] }
-    let(:dashboard) { described_class.new(*process_params).process }
+    let(:process_params) { [project, environment] }
+    let(:dashboard) { described_class.new(*process_params).process(dashboard_yml) }
 
     context 'when the dashboard references persisted metrics with alerts' do
       let!(:alert) do