Add dep on third_party/webgpu-headers

This way, we can eventually use the upstream header / .yml

Fixed: dawn:2556
Change-Id: I2e9138aa053117f2bf99c07c4f0a9a840629efe9
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/186660
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>
diff --git a/.gitmodules b/.gitmodules
index fb93a00..e666fb9 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -92,6 +92,9 @@
 	path = third_party/dxheaders
 	url = https://chromium.googlesource.com/external/github.com/microsoft/DirectX-Headers
 	gclient-condition = host_os != "win"
+[submodule "third_party/webgpu-headers"]
+	path = third_party/webgpu-headers
+	url = https://chromium.googlesource.com/external/github.com/webgpu-native/webgpu-headers
 [submodule "third_party/khronos/OpenGL-Registry"]
 	path = third_party/khronos/OpenGL-Registry
 	url = https://chromium.googlesource.com/external/github.com/KhronosGroup/OpenGL-Registry
diff --git a/DEPS b/DEPS
index fa18903..669e4f7 100644
--- a/DEPS
+++ b/DEPS
@@ -213,6 +213,10 @@
     'condition': 'host_os != "win"',
   },
 
+  'third_party/webgpu-headers': {
+    'url': '{chromium_git}/external/github.com/webgpu-native/webgpu-headers@aef5e428a1fdab2ea770581ae7c95d8779984e0a',
+  },
+
   'third_party/khronos/OpenGL-Registry': {
     'url': '{chromium_git}/external/github.com/KhronosGroup/OpenGL-Registry@5bae8738b23d06968e7c3a41308568120943ae77',
   },
diff --git a/third_party/webgpu-headers b/third_party/webgpu-headers
new file mode 160000
index 0000000..aef5e42
--- /dev/null
+++ b/third_party/webgpu-headers
@@ -0,0 +1 @@
+Subproject commit aef5e428a1fdab2ea770581ae7c95d8779984e0a