layers: Move desc set helper to descriptorset module

Change-Id: I695cf51b6fa27df7585582f545c0077efb9fd432
diff --git a/layers/descriptor_sets.h b/layers/descriptor_sets.h
index 7e0bc87..9d9a15d 100644
--- a/layers/descriptor_sets.h
+++ b/layers/descriptor_sets.h
@@ -285,6 +285,9 @@
 // "Perform" does the update with the assumption that ValidateUpdateDescriptorSets() has passed for the given update
 void PerformUpdateDescriptorSets(const core_validation::layer_data *, uint32_t, const VkWriteDescriptorSet *, uint32_t,
                                  const VkCopyDescriptorSet *);
+// Similar to PerformUpdateDescriptorSets, this function will do the same for updating via templates
+void PerformUpdateDescriptorSetsWithTemplateKHR(layer_data *, VkDescriptorSet, std::unique_ptr<TEMPLATE_STATE> const &,
+                                                const void *);
 // Validate that Allocation state is ok
 bool ValidateAllocateDescriptorSets(const debug_report_data *, const VkDescriptorSetAllocateInfo *,
                                     const core_validation::layer_data *, AllocateDescriptorSetsData *);