bind-gen: Implement NativeValueTraits for interface

Makes NativeValueTraits work well with the new generated
code of IDL interface.

Adds NativeValueTraits::ArgumentValue in addition to
NativeValue in order to produce better error messages.

Bug: 839389
Change-Id: I050dfa5b53c11aea6e50de5ef0148292db7fb3cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1995241
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#731179}

third_party/blink/renderer/bindings/core/v8/native_value_traits_impl.cc

@@ -37,6 +37,20 @@ ScriptWrappable* NativeValueTraitsInterfaceNativeValue(
   return ToScriptWrappable(value.As<v8::Object>());
 }
 
+ScriptWrappable* NativeValueTraitsInterfaceArgumentValue(
+    v8::Isolate* isolate,
+    const WrapperTypeInfo* wrapper_type_info,
+    int argument_index,
+    v8::Local<v8::Value> value,
+    ExceptionState& exception_state) {
+  if (!V8PerIsolateData::From(isolate)->HasInstance(wrapper_type_info, value)) {
+    exception_state.ThrowTypeError(ExceptionMessages::ArgumentNotOfType(
+        argument_index, wrapper_type_info->interface_name));
+    return nullptr;
+  }
+  return ToScriptWrappable(value.As<v8::Object>());
+}
+
 }  // namespace bindings
 
 #define DEFINE_NATIVE_VALUE_TRAITS_BUFFER_SOURCE_TYPE(T, V8T)             \

third_party/blink/renderer/bindings/core/v8/native_value_traits_impl.h

@@ -31,6 +31,13 @@ CORE_EXPORT ScriptWrappable* NativeValueTraitsInterfaceNativeValue(
     v8::Local<v8::Value> value,
     ExceptionState& exception_state);
 
+CORE_EXPORT ScriptWrappable* NativeValueTraitsInterfaceArgumentValue(
+    v8::Isolate* isolate,
+    const WrapperTypeInfo* wrapper_type_info,
+    int argument_index,
+    v8::Local<v8::Value> value,
+    ExceptionState& exception_state);
+
 }  // namespace bindings
 
 // Boolean
@@ -42,6 +49,13 @@ struct CORE_EXPORT NativeValueTraits<IDLBoolean>
                           ExceptionState& exception_state) {
     return ToBoolean(isolate, value, exception_state);
   }
+
+  static bool ArgumentValue(v8::Isolate* isolate,
+                            int argument_index,
+                            v8::Local<v8::Value> value,
+                            ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 // Integers
@@ -53,6 +67,13 @@ struct CORE_EXPORT NativeValueTraits<IDLByte>
                             ExceptionState& exception_state) {
     return ToInt8(isolate, value, kNormalConversion, exception_state);
   }
+
+  static int8_t ArgumentValue(v8::Isolate* isolate,
+                              int argument_index,
+                              v8::Local<v8::Value> value,
+                              ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -63,6 +84,13 @@ struct CORE_EXPORT NativeValueTraits<IDLOctet>
                              ExceptionState& exception_state) {
     return ToUInt8(isolate, value, kNormalConversion, exception_state);
   }
+
+  static uint8_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -73,6 +101,13 @@ struct CORE_EXPORT NativeValueTraits<IDLShort>
                              ExceptionState& exception_state) {
     return ToInt16(isolate, value, kNormalConversion, exception_state);
   }
+
+  static int16_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -83,6 +118,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnsignedShort>
                               ExceptionState& exception_state) {
     return ToUInt16(isolate, value, kNormalConversion, exception_state);
   }
+
+  static uint16_t ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -93,6 +135,13 @@ struct CORE_EXPORT NativeValueTraits<IDLLong>
                              ExceptionState& exception_state) {
     return ToInt32(isolate, value, kNormalConversion, exception_state);
   }
+
+  static int32_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -103,6 +152,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnsignedLong>
                               ExceptionState& exception_state) {
     return ToUInt32(isolate, value, kNormalConversion, exception_state);
   }
+
+  static uint32_t ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -113,6 +169,13 @@ struct CORE_EXPORT NativeValueTraits<IDLLongLong>
                              ExceptionState& exception_state) {
     return ToInt64(isolate, value, kNormalConversion, exception_state);
   }
+
+  static int64_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -123,6 +186,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnsignedLongLong>
                               ExceptionState& exception_state) {
     return ToUInt64(isolate, value, kNormalConversion, exception_state);
   }
+
+  static uint64_t ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 // [Clamp] Integers
@@ -134,6 +204,13 @@ struct CORE_EXPORT NativeValueTraits<IDLByteClamp>
                             ExceptionState& exception_state) {
     return ToInt8(isolate, value, kClamp, exception_state);
   }
+
+  static int8_t ArgumentValue(v8::Isolate* isolate,
+                              int argument_index,
+                              v8::Local<v8::Value> value,
+                              ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -144,6 +221,13 @@ struct CORE_EXPORT NativeValueTraits<IDLOctetClamp>
                              ExceptionState& exception_state) {
     return ToUInt8(isolate, value, kClamp, exception_state);
   }
+
+  static uint8_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -154,6 +238,13 @@ struct CORE_EXPORT NativeValueTraits<IDLShortClamp>
                              ExceptionState& exception_state) {
     return ToInt16(isolate, value, kClamp, exception_state);
   }
+
+  static int16_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -164,6 +255,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnsignedShortClamp>
                               ExceptionState& exception_state) {
     return ToUInt16(isolate, value, kClamp, exception_state);
   }
+
+  static uint16_t ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -174,6 +272,13 @@ struct CORE_EXPORT NativeValueTraits<IDLLongClamp>
                              ExceptionState& exception_state) {
     return ToInt32(isolate, value, kClamp, exception_state);
   }
+
+  static int32_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -184,6 +289,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnsignedLongClamp>
                               ExceptionState& exception_state) {
     return ToUInt32(isolate, value, kClamp, exception_state);
   }
+
+  static uint32_t ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -194,6 +306,13 @@ struct CORE_EXPORT NativeValueTraits<IDLLongLongClamp>
                              ExceptionState& exception_state) {
     return ToInt64(isolate, value, kClamp, exception_state);
   }
+
+  static int64_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -204,6 +323,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnsignedLongLongClamp>
                               ExceptionState& exception_state) {
     return ToUInt64(isolate, value, kClamp, exception_state);
   }
+
+  static uint64_t ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 // [EnforceRange] Integers
@@ -215,6 +341,13 @@ struct CORE_EXPORT NativeValueTraits<IDLByteEnforceRange>
                             ExceptionState& exception_state) {
     return ToInt8(isolate, value, kEnforceRange, exception_state);
   }
+
+  static int8_t ArgumentValue(v8::Isolate* isolate,
+                              int argument_index,
+                              v8::Local<v8::Value> value,
+                              ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -225,6 +358,13 @@ struct CORE_EXPORT NativeValueTraits<IDLOctetEnforceRange>
                              ExceptionState& exception_state) {
     return ToUInt8(isolate, value, kEnforceRange, exception_state);
   }
+
+  static uint8_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -235,6 +375,13 @@ struct CORE_EXPORT NativeValueTraits<IDLShortEnforceRange>
                              ExceptionState& exception_state) {
     return ToInt16(isolate, value, kEnforceRange, exception_state);
   }
+
+  static int16_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -245,6 +392,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnsignedShortEnforceRange>
                               ExceptionState& exception_state) {
     return ToUInt16(isolate, value, kEnforceRange, exception_state);
   }
+
+  static uint16_t ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -255,6 +409,13 @@ struct CORE_EXPORT NativeValueTraits<IDLLongEnforceRange>
                              ExceptionState& exception_state) {
     return ToInt32(isolate, value, kEnforceRange, exception_state);
   }
+
+  static int32_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -265,6 +426,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnsignedLongEnforceRange>
                               ExceptionState& exception_state) {
     return ToUInt32(isolate, value, kEnforceRange, exception_state);
   }
+
+  static uint32_t ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -275,6 +443,13 @@ struct CORE_EXPORT NativeValueTraits<IDLLongLongEnforceRange>
                              ExceptionState& exception_state) {
     return ToInt64(isolate, value, kEnforceRange, exception_state);
   }
+
+  static int64_t ArgumentValue(v8::Isolate* isolate,
+                               int argument_index,
+                               v8::Local<v8::Value> value,
+                               ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -285,6 +460,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnsignedLongLongEnforceRange>
                               ExceptionState& exception_state) {
     return ToUInt64(isolate, value, kEnforceRange, exception_state);
   }
+
+  static uint64_t ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 // Strings
@@ -434,6 +616,18 @@ struct NativeValueTraits<IDLByteStringBaseV2<mode>>
     }
     return bindings::NativeValueTraitsStringAdapter(v8_string);
   }
+
+  static bindings::NativeValueTraitsStringAdapter ArgumentValue(
+      v8::Isolate* isolate,
+      int argument_index,
+      v8::Local<v8::Value> value,
+      ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
+
+  static bindings::NativeValueTraitsStringAdapter NullValue() {
+    return bindings::NativeValueTraitsStringAdapter();
+  }
 };
 
 template <bindings::NativeValueTraitsStringConv mode>
@@ -469,6 +663,18 @@ struct NativeValueTraits<IDLStringBaseV2<mode>>
     }
     return bindings::NativeValueTraitsStringAdapter(v8_string);
   }
+
+  static bindings::NativeValueTraitsStringAdapter ArgumentValue(
+      v8::Isolate* isolate,
+      int argument_index,
+      v8::Local<v8::Value> value,
+      ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
+
+  static bindings::NativeValueTraitsStringAdapter NullValue() {
+    return bindings::NativeValueTraitsStringAdapter();
+  }
 };
 
 template <bindings::NativeValueTraitsStringConv mode>
@@ -485,6 +691,15 @@ struct NativeValueTraits<IDLUSVStringBaseV2<mode>>
 
     return ReplaceUnmatchedSurrogates(string);
   }
+
+  static String ArgumentValue(v8::Isolate* isolate,
+                              int argument_index,
+                              v8::Local<v8::Value> value,
+                              ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
+
+  static String NullValue() { return String(); }
 };
 
 // Floats and doubles
@@ -496,6 +711,13 @@ struct CORE_EXPORT NativeValueTraits<IDLDouble>
                             ExceptionState& exception_state) {
     return ToRestrictedDouble(isolate, value, exception_state);
   }
+
+  static double ArgumentValue(v8::Isolate* isolate,
+                              int argument_index,
+                              v8::Local<v8::Value> value,
+                              ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -506,6 +728,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnrestrictedDouble>
                             ExceptionState& exception_state) {
     return ToDouble(isolate, value, exception_state);
   }
+
+  static double ArgumentValue(v8::Isolate* isolate,
+                              int argument_index,
+                              v8::Local<v8::Value> value,
+                              ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -516,6 +745,13 @@ struct CORE_EXPORT NativeValueTraits<IDLFloat>
                            ExceptionState& exception_state) {
     return ToRestrictedFloat(isolate, value, exception_state);
   }
+
+  static float ArgumentValue(v8::Isolate* isolate,
+                             int argument_index,
+                             v8::Local<v8::Value> value,
+                             ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 template <>
@@ -526,6 +762,13 @@ struct CORE_EXPORT NativeValueTraits<IDLUnrestrictedFloat>
                            ExceptionState& exception_state) {
     return ToFloat(isolate, value, exception_state);
   }
+
+  static float ArgumentValue(v8::Isolate* isolate,
+                             int argument_index,
+                             v8::Local<v8::Value> value,
+                             ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 // Buffer source types
@@ -643,6 +886,13 @@ struct NativeValueTraits<IDLSequence<T>>
     return result;
   }
 
+  static ImplType ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
+
  private:
   // Fast case: we're interating over an Array that adheres to
   // %ArrayIteratorPrototype%'s protocol.
@@ -830,13 +1080,20 @@ struct NativeValueTraits<IDLRecord<K, V>>
     // "5. Return result."
     return result;
   }
+
+  static ImplType ArgumentValue(v8::Isolate* isolate,
+                                int argument_index,
+                                v8::Local<v8::Value> value,
+                                ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 // Callback functions
 template <typename T>
 struct NativeValueTraits<
     T,
-    std::enable_if_t<std::is_base_of<CallbackFunctionBase, T>::value>>
+    typename std::enable_if_t<std::is_base_of<CallbackFunctionBase, T>::value>>
     : public NativeValueTraitsBase<T> {
   static T* NativeValue(v8::Isolate* isolate,
                         v8::Local<v8::Value> value,
@@ -850,6 +1107,13 @@ struct NativeValueTraits<
         << "is not yet implemented.";
     return nullptr;
   }
+
+  static T* ArgumentValue(v8::Isolate* isolate,
+                          int argument_index,
+                          v8::Local<v8::Value> value,
+                          ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 // Dictionary
@@ -864,6 +1128,13 @@ struct NativeValueTraits<
                         ExceptionState& exception_state) {
     return T::Create(isolate, value, exception_state);
   }
+
+  static T* ArgumentValue(v8::Isolate* isolate,
+                          int argument_index,
+                          v8::Local<v8::Value> value,
+                          ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 // Interface
@@ -880,6 +1151,16 @@ struct NativeValueTraits<
         ->template ToImpl<T>();
   }
 
+  static T* ArgumentValue(v8::Isolate* isolate,
+                          int argument_index,
+                          v8::Local<v8::Value> value,
+                          ExceptionState& exception_state) {
+    return bindings::NativeValueTraitsInterfaceArgumentValue(
+               isolate, T::GetStaticWrapperTypeInfo(), argument_index, value,
+               exception_state)
+        ->template ToImpl<T>();
+  }
+
   static constexpr T* NullValue() { return nullptr; }
 };
 
@@ -897,6 +1178,14 @@ struct NativeValueTraits<IDLNullable<InnerType>>
     return NativeValueTraits<InnerType>::NativeValue(isolate, v8_value,
                                                      exception_state);
   }
+
+  static typename IDLNullable<InnerType>::ResultType ArgumentValue(
+      v8::Isolate* isolate,
+      int argument_index,
+      v8::Local<v8::Value> value,
+      ExceptionState& exception_state) {
+    return NativeValue(isolate, value, exception_state);
+  }
 };
 
 }  // namespace blink

third_party/blink/renderer/bindings/scripts/bind_gen/blink_v8_bridge.py

@@ -174,12 +174,13 @@ def native_value_tag(idl_type):
     assert isinstance(idl_type, web_idl.IdlType)
 
     real_type = idl_type.unwrap(typedef=True)
+    non_null_real_type = real_type.unwrap(nullable=True)
 
-    if (real_type.is_boolean or real_type.is_numeric or real_type.is_any
-            or real_type.is_object):
+    if (real_type.is_boolean or real_type.is_numeric
+            or non_null_real_type.is_any or non_null_real_type.is_object):
         return "IDL{}".format(real_type.type_name)
 
-    if real_type.unwrap(nullable=True).is_string:
+    if non_null_real_type.is_string:
         return "IDL{}V2".format(real_type.type_name)
 
     if real_type.is_symbol:
@@ -188,10 +189,10 @@ def native_value_tag(idl_type):
     if real_type.is_void:
         assert False, "Blink does not support/accept IDL void type."
 
-    if real_type.type_definition_object is not None:
-        return blink_type_info(real_type).value_t
+    if non_null_real_type.type_definition_object:
+        return blink_class_name(non_null_real_type.type_definition_object)
 
-    if real_type.is_sequence:
+    if real_type.is_sequence or real_type.is_frozen_array:
         return "IDLSequence<{}>".format(
             native_value_tag(real_type.element_type))
 
@@ -209,7 +210,7 @@ def native_value_tag(idl_type):
     if real_type.is_nullable:
         return "IDLNullable<{}>".format(native_value_tag(real_type.inner_type))
 
-    assert False
+    assert False, "Unknown type: {}".format(idl_type.syntactic_form)
 
 
 def make_default_value_expr(idl_type, default_value):
@@ -307,6 +308,7 @@ def make_default_value_expr(idl_type, default_value):
 def make_v8_to_blink_value(blink_var_name,
                            v8_value_expr,
                            idl_type,
+                           argument_index=None,
                            default_value=None):
     """
     Returns a SymbolNode whose definition converts a v8::Value to a Blink value.
@@ -314,6 +316,7 @@ def make_v8_to_blink_value(blink_var_name,
     assert isinstance(blink_var_name, str)
     assert isinstance(v8_value_expr, str)
     assert isinstance(idl_type, web_idl.IdlType)
+    assert (argument_index is None or isinstance(argument_index, (int, long)))
     assert (default_value is None
             or isinstance(default_value, web_idl.LiteralConstant))
 
@@ -321,10 +324,22 @@ def make_v8_to_blink_value(blink_var_name,
     F = lambda *args, **kwargs: T(_format(*args, **kwargs))
 
     def create_definition(symbol_node):
-        blink_value_expr = _format(
-            "NativeValueTraits<{_1}>::NativeValue({_2})",
-            _1=native_value_tag(idl_type),
-            _2=", ".join(["${isolate}", v8_value_expr, "${exception_state}"]))
+        if argument_index is None:
+            blink_value_expr = _format(
+                "NativeValueTraits<{_1}>::NativeValue({_2})",
+                _1=native_value_tag(idl_type),
+                _2=", ".join(
+                    ["${isolate}", v8_value_expr, "${exception_state}"]))
+        else:
+            blink_value_expr = _format(
+                "NativeValueTraits<{_1}>::ArgumentValue({_2})",
+                _1=native_value_tag(idl_type),
+                _2=", ".join([
+                    "${isolate}",
+                    str(argument_index),
+                    v8_value_expr,
+                    "${exception_state}",
+                ]))
 
         if default_value is None:
             return SymbolDefinitionNode(symbol_node, [

third_party/blink/renderer/bindings/scripts/bind_gen/interface.py

@@ -147,8 +147,12 @@ def bind_blink_api_arguments(code_node, cg_context):
         else:
             v8_value = "${{info}}[{}]".format(argument.index)
             code_node.register_code_symbol(
-                make_v8_to_blink_value(name, v8_value, argument.idl_type,
-                                       argument.default_value))
+                make_v8_to_blink_value(
+                    name,
+                    v8_value,
+                    argument.idl_type,
+                    argument_index=index,
+                    default_value=argument.default_value))
 
 
 def bind_callback_local_vars(code_node, cg_context):
@@ -2957,5 +2961,5 @@ def generate_interface(interface):
 
 
 def generate_interfaces(web_idl_database):
-    interface = web_idl_database.find("Navigator")
+    interface = web_idl_database.find("Node")
     generate_interface(interface)