loader: Fix enumerate device layer properties

Loader was calling down the chain when is needs to
respond with aggregate data. This patch fixes
https://buganizer.corp.google.com/u/0/issues/26982782

Change-Id: I236183d5d781a6efc3d84db4a51376b8cc29664f
diff --git a/vulkan/libvulkan/loader.cpp b/vulkan/libvulkan/loader.cpp
index a0c142e..345b114 100644
--- a/vulkan/libvulkan/loader.cpp
+++ b/vulkan/libvulkan/loader.cpp
@@ -861,15 +861,14 @@
     return *properties_count < num_extensions ? VK_INCOMPLETE : VK_SUCCESS;
 }
 
+// This is a no-op, the Top function returns the aggregate layer property
+// data. This is to keep the dispatch generator happy.
 VKAPI_ATTR
-VkResult EnumerateDeviceLayerProperties_Bottom(VkPhysicalDevice /*pdev*/,
-                                               uint32_t* properties_count,
-                                               VkLayerProperties* properties) {
-    uint32_t layer_count =
-        EnumerateDeviceLayers(properties ? *properties_count : 0, properties);
-    if (!properties || *properties_count > layer_count)
-        *properties_count = layer_count;
-    return *properties_count < layer_count ? VK_INCOMPLETE : VK_SUCCESS;
+VkResult EnumerateDeviceLayerProperties_Bottom(
+    VkPhysicalDevice /*pdev*/,
+    uint32_t* /*properties_count*/,
+    VkLayerProperties* /*properties*/) {
+    return VK_SUCCESS;
 }
 
 VKAPI_ATTR
@@ -1239,6 +1238,17 @@
 }
 
 VKAPI_ATTR
+VkResult EnumerateDeviceLayerProperties_Top(VkPhysicalDevice /*pdev*/,
+                                               uint32_t* properties_count,
+                                               VkLayerProperties* properties) {
+    uint32_t layer_count =
+        EnumerateDeviceLayers(properties ? *properties_count : 0, properties);
+    if (!properties || *properties_count > layer_count)
+        *properties_count = layer_count;
+    return *properties_count < layer_count ? VK_INCOMPLETE : VK_SUCCESS;
+}
+
+VKAPI_ATTR
 VkResult CreateDevice_Top(VkPhysicalDevice gpu,
                           const VkDeviceCreateInfo* create_info,
                           const VkAllocationCallbacks* allocator,