Remove VK_LUNARG_direct_driver_loading from supported extensions

This extension is only implemented by the Vulkan Loader, and as
clarified by the extension proposal text drivers don't need any
modification to support being directly loaded, except they need to
support "Loader-ICD interface version 7".

While SwiftShader has always exported the full set of Vulkan API entry
points as a convenience, and thus could be considered to take the place
of the Vulkan Loader under some circumstances, properly supporting this
extension would serve no purpose.

Bug: b/229112690
Change-Id: I16e46572cfb04329ddbe2bbcea135fb925366543
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/70548
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/Vulkan/libVulkan.cpp b/src/Vulkan/libVulkan.cpp
index f01fe3a..a182012 100644
--- a/src/Vulkan/libVulkan.cpp
+++ b/src/Vulkan/libVulkan.cpp
@@ -284,7 +284,6 @@
 	{ { VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME, VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_SPEC_VERSION } },
 	{ { VK_EXT_DEBUG_UTILS_EXTENSION_NAME, VK_EXT_DEBUG_UTILS_SPEC_VERSION } },
 	{ { VK_EXT_HEADLESS_SURFACE_EXTENSION_NAME, VK_EXT_HEADLESS_SURFACE_SPEC_VERSION } },
-	{ { VK_LUNARG_DIRECT_DRIVER_LOADING_EXTENSION_NAME, VK_LUNARG_DIRECT_DRIVER_LOADING_SPEC_VERSION } },
 #ifndef __ANDROID__
 	{ { VK_KHR_SURFACE_EXTENSION_NAME, VK_KHR_SURFACE_SPEC_VERSION } },
 	{ { VK_EXT_SURFACE_MAINTENANCE_1_EXTENSION_NAME, VK_EXT_SURFACE_MAINTENANCE_1_SPEC_VERSION } },
@@ -562,9 +561,8 @@
 			//  Vulkan structures in this Specification."
 			break;
 		case VK_STRUCTURE_TYPE_DIRECT_DRIVER_LOADING_LIST_LUNARG:
-			// This structure should only be used by the loader and should not be
-			// forwarded to the driver. Nevertheless, since SwiftShader does support
-			// this extension, we should not assert on it.
+			// TODO(b/229112690): This structure is only meant to be used by the Vulkan Loader
+			// and should not be forwarded to the driver.
 			break;
 		default:
 			UNSUPPORTED("pCreateInfo->pNext sType = %s", vk::Stringify(createInfo->sType).c_str());