fix build

Author: dnfield

shell/common/shell_unittests.cc

@@ -4623,6 +4623,9 @@ TEST_F(ShellTest, RuntimeStageBackendDefaultsToSkSLWithoutImpeller) {
   DestroyShell(std::move(shell), task_runners);
 }
 
+// TODO(dnfield): Enable GL and Vulkan after
+// https://github.com/flutter/flutter/issues/140419
+#if SHELL_ENABLE_METAL
 TEST_F(ShellTest, RuntimeStageBackendWithImpeller) {
   ASSERT_FALSE(DartVMRef::IsInstanceRunning());
   Settings settings = CreateSettingsForFixture();
@@ -4640,36 +4643,30 @@ TEST_F(ShellTest, RuntimeStageBackendWithImpeller) {
 
   fml::AutoResetWaitableEvent latch;
 
-  std::optional<impeller::Context::BackendType> impeller_backend;
+  impeller::Context::BackendType impeller_backend;
   fml::TaskRunner::RunNowOrPostTask(
       shell->GetTaskRunners().GetPlatformTaskRunner(),
       [platform_view = shell->GetPlatformView(), &latch, &impeller_backend]() {
         auto impeller_context = platform_view->GetImpellerContext();
-    // TODO(dnfield): Enable GL and Vulkan after
-    // https://github.com/flutter/flutter/issues/140419
-#if SHELL_ENABLE_METAL
         EXPECT_TRUE(impeller_context);
         impeller_backend = impeller_context->GetBackendType();
-#endif
         latch.Signal();
       });
   latch.Wait();
 
   AddNativeCallback(
       "NotifyNative", CREATE_NATIVE_ENTRY([&](auto args) {
         auto backend = UIDartState::Current()->GetRuntimeStageBackend();
-        if (impeller_backend.has_value()) {
-          switch (impeller_backend.value()) {
-            case impeller::Context::BackendType::kMetal:
-              EXPECT_EQ(backend, impeller::RuntimeStageBackend::kMetal);
-              break;
-            case impeller::Context::BackendType::kOpenGLES:
-              EXPECT_EQ(backend, impeller::RuntimeStageBackend::kOpenGLES);
-              break;
-            case impeller::Context::BackendType::kVulkan:
-              EXPECT_EQ(backend, impeller::RuntimeStageBackend::kVulkan);
-              break;
-          }
+        switch (impeller_backend) {
+          case impeller::Context::BackendType::kMetal:
+            EXPECT_EQ(backend, impeller::RuntimeStageBackend::kMetal);
+            break;
+          case impeller::Context::BackendType::kOpenGLES:
+            EXPECT_EQ(backend, impeller::RuntimeStageBackend::kOpenGLES);
+            break;
+          case impeller::Context::BackendType::kVulkan:
+            EXPECT_EQ(backend, impeller::RuntimeStageBackend::kVulkan);
+            break;
         }
         latch.Signal();
       }));
@@ -4682,6 +4679,7 @@ TEST_F(ShellTest, RuntimeStageBackendWithImpeller) {
 
   DestroyShell(std::move(shell), task_runners);
 }
+#endif  // SHELL_ENABLE_METAL
 
 }  // namespace testing
 }  // namespace flutter