Mix `url_helpers` into `Ci::Build`

app/models/ci/build.rb

@@ -34,6 +34,7 @@
 
 module Ci
   class Build < CommitStatus
+    include Gitlab::Application.routes.url_helpers
     LAZY_ATTRIBUTES = ['trace']
 
     belongs_to :runner, class_name: 'Ci::Runner'
@@ -291,20 +292,17 @@ module Ci
     end
 
     def target_url
-      Gitlab::Application.routes.url_helpers.
       namespace_project_build_url(project.namespace, project, self)
     end
 
     def cancel_url
       if active?
-        Gitlab::Application.routes.url_helpers.
         cancel_namespace_project_build_path(project.namespace, project, self)
       end
     end
 
     def retry_url
       if retryable?
-        Gitlab::Application.routes.url_helpers.
         retry_namespace_project_build_path(project.namespace, project, self)
       end
     end
@@ -323,14 +321,12 @@ module Ci
 
     def download_url
       if artifacts_file.exists?
-        Gitlab::Application.routes.url_helpers.
         download_namespace_project_build_artifacts_path(project.namespace, project, self)
       end
     end
 
     def artifacts_browse_url
       if artifacts_file.exists?
-        Gitlab::Application.routes.url_helpers.
         browse_namespace_project_build_artifacts_path(project.namespace, project, self)
       end
     end