[Impeller] Remove unactionable error logs and use structure chains for instance creation.

impeller/renderer/backend/vulkan/context_vk.cc

@@ -185,28 +185,21 @@ void ContextVK::Setup(Settings settings) {
   application_info.setPEngineName("Impeller");
   application_info.setPApplicationName("Impeller");
 
+  vk::StructureChain<vk::InstanceCreateInfo, vk::ValidationFeaturesEXT>
+      instance_chain;
+
+  if (!caps->AreValidationsEnabled()) {
+    instance_chain.unlink<vk::ValidationFeaturesEXT>();
+  }
+
   std::vector<vk::ValidationFeatureEnableEXT> enabled_validations = {
       vk::ValidationFeatureEnableEXT::eSynchronizationValidation,
   };
 
-  vk::ValidationFeaturesEXT validation;
+  auto validation = instance_chain.get<vk::ValidationFeaturesEXT>();
   validation.setEnabledValidationFeatures(enabled_validations);
 
-  vk::InstanceCreateInfo instance_info;
-  if (caps->AreValidationsEnabled()) {
-    std::stringstream ss;
-    ss << "Enabling validation layers, features: [";
-    for (const auto& validation : enabled_validations) {
-      ss << vk::to_string(validation) << " ";
-    }
-    ss << "]";
-    FML_LOG(ERROR) << ss.str();
-#if !defined(IMPELLER_ENABLE_VULKAN_VALIDATION_LAYERS) && FML_OS_ANDROID
-    FML_LOG(ERROR) << "Vulkan validation layers turned on but the gn argument "
-                      "`--enable-vulkan-validation-layers` is missing.";
-#endif
-    instance_info.pNext = &validation;
-  }
+  auto instance_info = instance_chain.get<vk::InstanceCreateInfo>();
   instance_info.setPEnabledLayerNames(enabled_layers_c);
   instance_info.setPEnabledExtensionNames(enabled_extensions_c);
   instance_info.setPApplicationInfo(&application_info);