bindings: Skip undefined property descriptors when creating records.

third_party/WebKit/Source/bindings/core/v8/NativeValueTraitsImpl.h

Index: third_party/WebKit/Source/bindings/core/v8/NativeValueTraitsImpl.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/NativeValueTraitsImpl.h b/third_party/WebKit/Source/bindings/core/v8/NativeValueTraitsImpl.h
index 1713d4f5883928e0666bec081d44b41a0248a800..587075504827033dfa87483db6c913a79ac693e9 100644
--- a/third_party/WebKit/Source/bindings/core/v8/NativeValueTraitsImpl.h
+++ b/third_party/WebKit/Source/bindings/core/v8/NativeValueTraitsImpl.h
@@ -375,6 +375,8 @@ struct NativeValueTraits<IDLRecord<K, V>>
       // GetOwnPropertyDescriptor is responsible for catching any exceptions
       // and failures, and if we got to this point of the code we have a proper
       // object that was not created by a user.
+      if (desc->IsUndefined())
+        continue;
       DCHECK(desc->IsObject());
       v8::Local<v8::Value> enumerable =
           v8::Local<v8::Object>::Cast(desc)