Call vulnerability statistics update service

Call `Vulnerabilities::Statistics::UpdateService` service class from
the service classes where we update the state of vulnerability.

ee/app/services/vulnerabilities/base_service.rb

@@ -16,6 +16,7 @@ module Vulnerabilities
       return false unless vulnerability.update(params)
 
       SystemNoteService.change_vulnerability_state(vulnerability, @user) if vulnerability.state_previously_changed?
+      Vulnerabilities::Statistics::UpdateService.update_for(vulnerability)
       true
     end
 

ee/app/services/vulnerabilities/create_service.rb

@@ -20,6 +20,7 @@ module Vulnerabilities
         finding = @project.vulnerability_findings.lock_for_confirmation!(@finding_id)
 
         save_vulnerability(vulnerability, finding)
+        Statistics::UpdateService.update_for(vulnerability)
       rescue ActiveRecord::RecordNotFound
         vulnerability.errors.add(:base, _('finding is not found or is already attached to a vulnerability'))
         raise ActiveRecord::Rollback

ee/app/services/vulnerabilities/statistics/update_service.rb

+# frozen_string_literal: true
+
+module Vulnerabilities
+  module Statistics
+    class UpdateService
+      def self.update_for(vulnerability)
+        new(vulnerability).execute
+      end
+
+      def initialize(vulnerability)
+        self.vulnerability = vulnerability
+      end
+
+      def execute
+
+      end
+
+      private
+
+      attr_accessor :vulnerability
+
+      def stat_diff
+        @stat_diff ||= vulnerability.stat_diff
+      end
+    end
+  end
+end

ee/app/services/vulnerabilities/update_service.rb

@@ -18,6 +18,7 @@ module Vulnerabilities
       raise Gitlab::Access::AccessDeniedError unless can?(author, :create_vulnerability, project)
 
       vulnerability.update!(vulnerability_params)
+      Statistics::UpdateService.update_for(vulnerability)
 
       vulnerability
     end

ee/spec/services/vulnerabilities/confirm_service_spec.rb

@@ -21,6 +21,8 @@ RSpec.describe Vulnerabilities::ConfirmService do
       project.add_developer(user)
     end
 
+    it_behaves_like 'calls Vulnerabilities::Statistics::UpdateService'
+
     it 'confirms a vulnerability' do
       Timecop.freeze do
         confirm_vulnerability

ee/spec/services/vulnerabilities/create_service_spec.rb

@@ -20,6 +20,8 @@ RSpec.describe Vulnerabilities::CreateService do
       project.add_developer(user)
     end
 
+    it_behaves_like 'calls Vulnerabilities::Statistics::UpdateService'
+
     it 'creates a vulnerability from finding and attaches it to the vulnerability' do
       expect { subject }.to change { project.vulnerabilities.count }.by(1)
       expect(project.vulnerabilities.last).to(

ee/spec/services/vulnerabilities/dismiss_service_spec.rb

@@ -21,6 +21,8 @@ RSpec.describe Vulnerabilities::DismissService do
       project.add_developer(user)
     end
 
+    it_behaves_like 'calls Vulnerabilities::Statistics::UpdateService'
+
     it 'dismisses a vulnerability and its associated findings' do
       Timecop.freeze do
         dismiss_vulnerability

ee/spec/services/vulnerabilities/resolve_service_spec.rb

@@ -21,6 +21,8 @@ RSpec.describe Vulnerabilities::ResolveService do
       project.add_developer(user)
     end
 
+    it_behaves_like 'calls Vulnerabilities::Statistics::UpdateService'
+
     it 'resolves a vulnerability' do
       Timecop.freeze do
         resolve_vulnerability

ee/spec/services/vulnerabilities/update_service_spec.rb

@@ -22,6 +22,8 @@ RSpec.describe Vulnerabilities::UpdateService do
       project.add_developer(user)
     end
 
+    it_behaves_like 'calls Vulnerabilities::Statistics::UpdateService'
+
     context 'when neither severity nor confidence are overridden' do
       it 'updates the vulnerability from updated finding (title, severity and confidence only)', :aggregate_failures do
         expect { subject }.not_to change { project.vulnerabilities.count }

ee/spec/support/shared_examples/services/vulnerabilities/calls_vulnerabilities_statistics_update_service_shared_example.rb

+# frozen_string_literal: true
+
+RSpec.shared_examples 'calls Vulnerabilities::Statistics::UpdateService' do
+  before do
+    allow(Vulnerabilities::Statistics::UpdateService).to receive(:update_for)
+  end
+
+  it 'calls the service class' do
+    subject
+
+    expect(Vulnerabilities::Statistics::UpdateService).to have_received(:update_for)
+  end
+end