Diagnostics: Remove hardcoded kCpuStress

- Currently, the CPU stress routine is always passed to
   `OnStandardRoutineResult`. This change correctly reports the
   routine type when a routine fails to start.

Bug: 1227792
Change-Id: Ifa17d5722b5b415c26b57f3967de10993bd413cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3018424
Commit-Queue: Michael Checo <michaelcheco@google.com>
Commit-Queue: Zentaro Kavanagh <zentaro@chromium.org>
Auto-Submit: Michael Checo <michaelcheco@google.com>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#900580}

ash/webui/diagnostics_ui/backend/system_routine_controller.cc

@@ -312,7 +312,7 @@ void SystemRoutineController::OnRoutineStarted(
   if (response_ptr->status ==
           healthd::DiagnosticRoutineStatusEnum::kFailedToStart ||
       response_ptr->id == healthd::kFailedToStartId) {
-    OnStandardRoutineResult(mojom::RoutineType::kCpuStress,
+    OnStandardRoutineResult(routine_type,
                             TestStatusToResult(response_ptr->status));
     return;
   }

ash/webui/diagnostics_ui/backend/system_routine_controller_unittest.cc

@@ -809,6 +809,27 @@ TEST_F(SystemRoutineControllerTest, RoutineResultEmitted) {
                                       /*expected_count=*/1);
 }
 
+TEST_F(SystemRoutineControllerTest,
+       RoutineFailedToStartCalledWithCorrectRoutineType) {
+  SetRunRoutineResponse(healthd::kFailedToStartId,
+                        healthd::DiagnosticRoutineStatusEnum::kFailedToStart);
+
+  base::HistogramTester histogram_tester;
+  FakeRoutineRunner routine_runner;
+  system_routine_controller_->RunRoutine(
+      mojom::RoutineType::kCpuCache,
+      routine_runner.receiver.BindNewPipeAndPassRemote());
+  base::RunLoop().RunUntilIdle();
+
+  EXPECT_FALSE(routine_runner.result.is_null());
+  VerifyRoutineResult(*routine_runner.result, mojom::RoutineType::kCpuCache,
+                      mojom::StandardRoutineResult::kUnableToRun);
+  histogram_tester.ExpectUniqueSample(
+      "ChromeOS.DiagnosticsUi.CpuCacheResult",
+      mojom::StandardRoutineResult::kUnableToRun,
+      /*expected_count=*/1);
+}
+
 TEST_F(SystemRoutineControllerTest, MemoryRuntimeEmitted) {
   // Run the CpuStress routine.
   SetRunRoutineResponse(/*id=*/1,