bindings: Add a migration adapter of IDL compilers

The code generator will be updated soon (issue 839389), and the new
generator does not generate WTF::String for IDL enumerations.
In gpu_device.cc, the return type of descriptor->extensions() in the
constructor will be Vector<V8GPUExtensionName> from Vector<String>.

This CL as an adapter function to make the generators migration easy.
The function makes a Vector<String> from either of Vector<String> or
Vector<V8GPUExtensionName>.


Bug: 839389, 1092328
Change-Id: Ib3c96f1509fa3ba1986222a13f591b42b9759258
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2352258
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799021}

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

@@ -8,6 +8,7 @@
 #include "third_party/blink/public/platform/platform.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_promise_resolver.h"
 #include "third_party/blink/renderer/bindings/modules/v8/v8_gpu_device_descriptor.h"
+#include "third_party/blink/renderer/bindings/modules/v8/v8_gpu_extension_name.h"
 #include "third_party/blink/renderer/bindings/modules/v8/v8_gpu_uncaptured_error_event_init.h"
 #include "third_party/blink/renderer/core/dom/dom_exception.h"
 #include "third_party/blink/renderer/core/inspector/console_message.h"
@@ -32,6 +33,20 @@
 
 namespace blink {
 
+namespace {
+
+#ifdef USE_BLINK_V8_BINDING_NEW_IDL_DICTIONARY
+Vector<String> ToStringVector(
+    const Vector<V8GPUExtensionName>& gpu_extension_names) {
+  Vector<String> result;
+  for (auto& name : gpu_extension_names)
+    result.push_back(IDLEnumAsString(name));
+  return result;
+}
+#endif
+
+}  // anonymous namespace
+
 // TODO(enga): Handle adapter options and device descriptor
 GPUDevice::GPUDevice(ExecutionContext* execution_context,
                      scoped_refptr<DawnControlClientHolder> dawn_control_client,
@@ -43,7 +58,11 @@ GPUDevice::GPUDevice(ExecutionContext* execution_context,
                  client_id,
                  dawn_control_client->GetInterface()->GetDevice(client_id)),
       adapter_(adapter),
+#ifdef USE_BLINK_V8_BINDING_NEW_IDL_DICTIONARY
+      extension_name_list_(ToStringVector(descriptor->extensions())),
+#else
       extension_name_list_(descriptor->extensions()),
+#endif
       queue_(MakeGarbageCollected<GPUQueue>(
           this,
           GetProcs().deviceGetDefaultQueue(GetHandle()))),