enable validation.

impeller/renderer/backend/vulkan/context_vk.cc

@@ -158,7 +158,7 @@ void ContextVK::Setup(Settings settings) {
   // 1. The user has explicitly enabled it.
   // 2. We are in a combination of debug mode, and running on Android.
   // (It's possible 2 is overly conservative and we can simplify this)
-  auto enable_validation = false; //settings.enable_validation;
+  auto enable_validation = settings.enable_validation;
 
 #if defined(FML_OS_ANDROID) && !defined(NDEBUG)
   enable_validation = true;