Minor vector sizing change. (#10753)

Summary: Minor change to reserve size for VkWriteDescriptorSet and
VkDescriptorSetLayoutBinding vectors.

Differential Revision: D74335276

Author: trivedivivek

backends/vulkan/runtime/vk_api/Descriptor.cpp

@@ -154,6 +154,7 @@ DescriptorSet& DescriptorSet::bind(
 
 VkDescriptorSet DescriptorSet::get_bind_handle() const {
   std::vector<VkWriteDescriptorSet> write_descriptor_sets;
+  write_descriptor_sets.reserve(bindings_.size());
 
   for (const ResourceBinding& binding : bindings_) {
     VkWriteDescriptorSet write{
@@ -185,9 +186,7 @@ VkDescriptorSet DescriptorSet::get_bind_handle() const {
       0u,
       nullptr);
 
-  VkDescriptorSet ret = handle_;
-
-  return ret;
+  return handle_;
 }
 
 void DescriptorSet::add_binding(const ResourceBinding& binding) {

backends/vulkan/runtime/vk_api/Shader.cpp

@@ -59,10 +59,11 @@ ShaderLayout::ShaderLayout(
     const ShaderLayout::Signature& signature)
     : device_(device), handle_{VK_NULL_HANDLE} {
   std::vector<VkDescriptorSetLayoutBinding> bindings;
+  bindings.reserve(signature.size());
 
   uint32_t binding_num = 0u;
   for (const VkDescriptorType type : signature) {
-    bindings.push_back({
+    bindings.emplace_back(VkDescriptorSetLayoutBinding{
         binding_num++, // binding
         type, // descriptorType
         1u, // descriptorCount