Add compute pipeline cache key generation for Vulkan.

- Adds dependency to vulkan-tools for pNext chain helpers.
- Adds extra caching to vulkan shaders to keep the spirv in the in-memory cache as well.
- Adds pNext chain serializer infra for Vulkan.

Change-Id: Ibe73183fbff15f7310eaaeae92fbd622be1ac096
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/85022
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Loko Kung <lokokung@google.com>

scripts/dawn_overrides_with_defaults.gni

@@ -54,14 +54,17 @@ if (!defined(dawn_swiftshader_dir)) {
   dawn_swiftshader_dir = ""
 }
 
-if (!defined(dawn_vulkan_headers_dir)) {
-  dawn_vulkan_headers_dir = "//third_party/vulkan-deps/vulkan-headers/src"
+if (!defined(dawn_vulkan_deps_dir)) {
+  dawn_vulkan_deps_dir = "//third_party/vulkan-deps"
   if (dawn_standalone) {
-    dawn_vulkan_headers_dir =
-        "${dawn_root}/third_party/vulkan-deps/vulkan-headers/src"
+    dawn_vulkan_deps_dir = "${dawn_root}/third_party/vulkan-deps"
   }
 }
 
+if (!defined(dawn_vulkan_headers_dir)) {
+  dawn_vulkan_headers_dir = "${dawn_vulkan_deps_dir}/vulkan-headers/src"
+}
+
 if (!defined(dawn_vulkan_loader_dir)) {
   # Default to the Vulkan loader not being available except in standalone.
   dawn_vulkan_loader_dir = ""
@@ -70,6 +73,10 @@ if (!defined(dawn_vulkan_loader_dir)) {
   }
 }
 
+if (!defined(dawn_vulkan_tools_dir)) {
+  dawn_vulkan_tools_dir = "${dawn_vulkan_deps_dir}/vulkan-tools/src"
+}
+
 if (!defined(dawn_vulkan_validation_layers_dir)) {
   # Default to VVLs not being available.
   dawn_vulkan_validation_layers_dir = ""