Add remote tunnel variable for e2e tests

qa/qa/runtime/browser.rb

@@ -143,6 +143,7 @@ module QA
           if QA::Runtime::Env.remote_grid
             selenium_options[:url] = QA::Runtime::Env.remote_grid
             capabilities[:browserVersion] = 'latest'
+            capabilities['sauce:options'] = { tunnelIdentifier: QA::Runtime::Env.remote_tunnel_id }
           end
 
           Capybara::Selenium::Driver.new(

qa/qa/runtime/env.rb

@@ -142,6 +142,10 @@ module QA
         ENV['QA_REMOTE_GRID_PROTOCOL'] || 'http'
       end
 
+      def remote_tunnel_id
+        ENV['QA_REMOTE_TUNNEL_ID'] || 'gitlab-sl_tunnel_id'
+      end
+
       def browser
         ENV['QA_BROWSER'].nil? ? :chrome : ENV['QA_BROWSER'].to_sym
       end