WebGPU: Create error shader module when the shader contains \0

This patch creates an error GPUShaderModule when the WGSL shader code
contains '\0' as the WebGPU SPEC doesn't allow having '\0' in any WGSL
shader. As any characters in WGSL comments will be ignored in Tint, we
can only do this check before passing the WGSL shader code into Tint.

Fixed: dawn:1345
Change-Id: Ic915354c36f416f4058b5c88a4579725b44827bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4568588
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Jiawei Shao <jiawei.shao@intel.com>
Cr-Commit-Position: refs/heads/main@{#1150226}

third_party/blink/renderer/modules/webgpu/gpu_shader_module.cc

@@ -36,16 +36,18 @@ GPUShaderModule* GPUShaderModule::Create(
   WGPUShaderModuleDescriptor dawn_desc = {};
 
   const auto* wgsl_or_spirv = webgpu_desc->code();
+  bool has_null_character = false;
   switch (wgsl_or_spirv->GetContentType()) {
     case V8UnionUSVStringOrUint32Array::ContentType::kUSVString: {
-      // `\0` is not allowed in WGSL but it is allowed in USVString
-      // By replacing `\0` with `\0xFFFD` we can safely pass this string
-      // to Dawn and it should generate an error.
-      wgsl_code = UTF8StringFromUSVStringWithNullReplacedByReplacementCodePoint(
-          wgsl_or_spirv->GetAsUSVString());
+      WTF::String wtf_wgsl_code(wgsl_or_spirv->GetAsUSVString());
+      wgsl_code = wtf_wgsl_code.Utf8();
       wgsl_desc.chain.sType = WGPUSType_ShaderModuleWGSLDescriptor;
       wgsl_desc.code = wgsl_code.c_str();
       dawn_desc.nextInChain = reinterpret_cast<WGPUChainedStruct*>(&wgsl_desc);
+      if (wtf_wgsl_code.find('\0') != WTF::kNotFound) {
+        has_null_character = true;
+      }
+
       break;
     }
     case V8UnionUSVStringOrUint32Array::ContentType::kUint32Array: {
@@ -71,9 +73,17 @@ GPUShaderModule* GPUShaderModule::Create(
     dawn_desc.label = label.c_str();
   }
 
-  GPUShaderModule* shader = MakeGarbageCollected<GPUShaderModule>(
-      device, device->GetProcs().deviceCreateShaderModule(device->GetHandle(),
-                                                          &dawn_desc));
+  WGPUShaderModule shader_module;
+  if (has_null_character) {
+    shader_module = device->GetProcs().deviceCreateErrorShaderModule(
+        device->GetHandle(), &dawn_desc,
+        "The WGSL shader contains an illegal character '\\0'");
+  } else {
+    shader_module = device->GetProcs().deviceCreateShaderModule(
+        device->GetHandle(), &dawn_desc);
+  }
+  GPUShaderModule* shader =
+      MakeGarbageCollected<GPUShaderModule>(device, shader_module);
   if (webgpu_desc->hasLabel())
     shader->setLabel(webgpu_desc->label());
   return shader;