layers: Added getSwapchainNode() helper

Added getSwapchainNode() helper to core_validation and update
DescriptorSet class to use it.
diff --git a/layers/descriptor_sets.cpp b/layers/descriptor_sets.cpp
index 2393d30..8ccd334 100644
--- a/layers/descriptor_sets.cpp
+++ b/layers/descriptor_sets.cpp
@@ -264,9 +264,8 @@
     : required_descriptors_by_type{}, layout_nodes(count, nullptr) {}
 
 cvdescriptorset::DescriptorSet::DescriptorSet(const VkDescriptorSet set, const DescriptorSetLayout *layout,
-                                              const core_validation::layer_data *dev_data,
-                                              const std::unordered_map<VkSwapchainKHR, SWAPCHAIN_NODE *> *swapchain_map)
-    : some_update_(false), set_(set), p_layout_(layout), device_data_(dev_data), swapchain_map_(swapchain_map) {
+                                              const core_validation::layer_data *dev_data)
+    : some_update_(false), set_(set), p_layout_(layout), device_data_(dev_data) {
     // Foreach binding, create default descriptors of given type
     for (uint32_t i = 0; i < p_layout_->GetBindingCount(); ++i) {
         auto type = p_layout_->GetTypeFromIndex(i);
@@ -581,7 +580,6 @@
 
 bool cvdescriptorset::ValidateImageUpdate(VkImageView image_view, VkImageLayout image_layout, VkDescriptorType type,
                                           const core_validation::layer_data *dev_data,
-                                          const std::unordered_map<VkSwapchainKHR, SWAPCHAIN_NODE *> *swapchain_map,
                                           std::string *error) {
     auto iv_data = getImageViewData(dev_data, image_view);
     if (!iv_data) {
@@ -604,9 +602,9 @@
         // Also need to check the swapchains.
         auto swapchain = getSwapchainFromImage(dev_data, image);
         if (swapchain) {
-            auto swapchain_pair = swapchain_map->find(swapchain);
-            if (swapchain_pair != swapchain_map->end()) {
-                format = swapchain_pair->second->createInfo.imageFormat;
+            auto swapchain_node = getSwapchainNode(dev_data, swapchain);
+            if (swapchain_node) {
+                format = swapchain_node->createInfo.imageFormat;
             }
         }
     }
@@ -1028,7 +1026,7 @@
             // Validate image
             auto image_view = update->pImageInfo[di].imageView;
             auto image_layout = update->pImageInfo[di].imageLayout;
-            if (!ValidateImageUpdate(image_view, image_layout, update->descriptorType, device_data_, swapchain_map_, error)) {
+            if (!ValidateImageUpdate(image_view, image_layout, update->descriptorType, device_data_, error)) {
                 std::stringstream error_str;
                 error_str << "Attempted write update to combined image sampler descriptor failed due to: " << error->c_str();
                 *error = error_str.str();
@@ -1059,7 +1057,7 @@
         for (uint32_t di = 0; di < update->descriptorCount; ++di) {
             auto image_view = update->pImageInfo[di].imageView;
             auto image_layout = update->pImageInfo[di].imageLayout;
-            if (!ValidateImageUpdate(image_view, image_layout, update->descriptorType, device_data_, swapchain_map_, error)) {
+            if (!ValidateImageUpdate(image_view, image_layout, update->descriptorType, device_data_, error)) {
                 std::stringstream error_str;
                 error_str << "Attempted write update to image descriptor failed due to: " << error->c_str();
                 *error = error_str.str();
@@ -1149,7 +1147,7 @@
             // Validate image
             auto image_view = img_samp_desc->GetImageView();
             auto image_layout = img_samp_desc->GetImageLayout();
-            if (!ValidateImageUpdate(image_view, image_layout, type, device_data_, swapchain_map_, error)) {
+            if (!ValidateImageUpdate(image_view, image_layout, type, device_data_, error)) {
                 std::stringstream error_str;
                 error_str << "Attempted copy update to combined image sampler descriptor failed due to: " << error->c_str();
                 *error = error_str.str();
@@ -1162,7 +1160,7 @@
             auto img_desc = static_cast<const ImageDescriptor *>(src_set->descriptors_[index + di].get());
             auto image_view = img_desc->GetImageView();
             auto image_layout = img_desc->GetImageLayout();
-            if (!ValidateImageUpdate(image_view, image_layout, type, device_data_, swapchain_map_, error)) {
+            if (!ValidateImageUpdate(image_view, image_layout, type, device_data_, error)) {
                 std::stringstream error_str;
                 error_str << "Attempted copy update to image descriptor failed due to: " << error->c_str();
                 *error = error_str.str();
@@ -1268,11 +1266,12 @@
     return skip_call;
 }
 // Decrement allocated sets from the pool and insert new sets into set_map
-void cvdescriptorset::PerformAllocateDescriptorSets(
-    const VkDescriptorSetAllocateInfo *p_alloc_info, const VkDescriptorSet *descriptor_sets,
-    const AllocateDescriptorSetsData *ds_data, std::unordered_map<VkDescriptorPool, DESCRIPTOR_POOL_NODE *> *pool_map,
-    std::unordered_map<VkDescriptorSet, cvdescriptorset::DescriptorSet *> *set_map, const core_validation::layer_data *dev_data,
-    const std::unordered_map<VkSwapchainKHR, SWAPCHAIN_NODE *> &swapchain_map) {
+void cvdescriptorset::PerformAllocateDescriptorSets(const VkDescriptorSetAllocateInfo *p_alloc_info,
+                                                    const VkDescriptorSet *descriptor_sets,
+                                                    const AllocateDescriptorSetsData *ds_data,
+                                                    std::unordered_map<VkDescriptorPool, DESCRIPTOR_POOL_NODE *> *pool_map,
+                                                    std::unordered_map<VkDescriptorSet, cvdescriptorset::DescriptorSet *> *set_map,
+                                                    const core_validation::layer_data *dev_data) {
     auto pool_state = (*pool_map)[p_alloc_info->descriptorPool];
     /* Account for sets and individual descriptors allocated from pool */
     pool_state->availableSets -= p_alloc_info->descriptorSetCount;
@@ -1283,7 +1282,7 @@
      * global map and the pool's set.
      */
     for (uint32_t i = 0; i < p_alloc_info->descriptorSetCount; i++) {
-        auto new_ds = new cvdescriptorset::DescriptorSet(descriptor_sets[i], ds_data->layout_nodes[i], dev_data, &swapchain_map);
+        auto new_ds = new cvdescriptorset::DescriptorSet(descriptor_sets[i], ds_data->layout_nodes[i], dev_data);
 
         pool_state->sets.insert(new_ds);
         new_ds->in_use.store(0);