Diagnostics: Add a short delay when running fake routines

Bug: 1125150
Test: browser_tests --gtest_filter=DiagnosticsApp*
Change-Id: Ia8a7c82359c99a71affc476e4eba002ce73702ae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2518191
Auto-Submit: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823714}

chromeos/components/diagnostics_ui/resources/mojo_interface_provider.js

@@ -45,6 +45,9 @@ function setupFakeSystemRoutineController_() {
   // Create controller.
   let controller = new FakeSystemRoutineController();
 
+  // Add a small delay while running fake routines.
+  controller.setDelayTimeInMillisecondsForTesting(2000);
+
   // Set the fake controller.
   setSystemRoutineControllerForTesting(controller);
 }