WebGPU: GPUVertexBufferDescriptor.stride member should be GPUBufferSize

This is to match the spec change[1].

[1] https://github.com/gpuweb/gpuweb/pull/423/files#diff-599c3a4f36042dec5cdc606f3c30dc38R913

Bug: 877147
Change-Id: I3fcf6505fd69caa6b3932145f937bc1b523b9244
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1844526Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: François Beaufort <beaufort.francois@gmail.com>
Commit-Queue: Jinho Bang <jinho.bang@samsung.com>
Cr-Commit-Position: refs/heads/master@{#703363}

third_party/blink/renderer/modules/webgpu/gpu_vertex_buffer_descriptor.idl

@@ -5,7 +5,7 @@
 // https://gpuweb.github.io/gpuweb/
 
 dictionary GPUVertexBufferDescriptor {
-    required unsigned long long stride;
+    required GPUBufferSize stride;
     GPUInputStepMode stepMode = "vertex";
     required sequence<GPUVertexAttributeDescriptor> attributeSet;
 };