Use the current context as the creation context for cross-origin objects.

third_party/WebKit/Source/bindings/templates/attributes.cpp.tmpl

 {% from 'utilities.cpp.tmpl' import declare_enum_validation_variable, v8_value_to_local_cpp_value %}
 
 {##############################################################################}
 {% macro attribute_getter(attribute, world_suffix) %}
+{% if attribute.has_cross_origin_getter %}
+static void {{attribute.name}}CrossOriginAttributeGetter(
+    const v8::PropertyCallbackInfo<v8::Value>& info) {
+  v8::Local<v8::Object> holder = info.Holder();
+  {{cpp_class}}* impl = {{v8_class}}::toImpl(holder);
+
+  {% if attribute.cpp_value_original %}
+  {{attribute.cpp_type}} {{attribute.cpp_value}}({{attribute.cpp_value_original}});
+  {% endif %}
+
+  {% if attribute.is_keep_alive_for_gc %}
+  // Keep the wrapper object for the return value alive as long as |this|
+  // object is alive in order to save creation time of the wrapper object.
+  if ({{attribute.cpp_value}} && DOMDataStore::setReturnValue(info.GetReturnValue(), {{attribute.cpp_value}}))
+    return;
+
+  // https://whatwg.org/C/browsers.html#crossorigingetownpropertyhelper-(-o,-p-)
+  //
+  //   If e.[[NeedsGet]] is true, then set crossOriginGet to an anonymous
+  //   built-in function, created in the current Realm Record, that performs the
+  //   same steps as the getter of the IDL attribute P on object O.
+  //
+  // However, the spec doesn't say exactly how this would work. The cross-origin
+  // |holder| object may not have a creation context associated with it. The
+  // current discussion on https://github.com/whatwg/html/issues/2273 suggests
+  // that crossOriginGet should return an origin-appropriate wrapper for Location
+  // associated with the current Realm record.
+  //
+  // This attempts to follow that suggestion by using the current context as the
+  // creation context rather than the creation context of |holder|.
+  v8::Isolate* isolate = info.GetIsolate();
+  v8::Local<v8::Value> v8Value(ToV8({{attribute.cpp_value}}, isolate->GetCurrentContext()->Global(), isolate));
+  const char kKeepAliveKey[] = "KeepAlive#{{interface_name}}#{{attribute.name}}";
+  V8HiddenValue::setHiddenValue(ScriptState::current(info.GetIsolate()), holder, v8AtomicString(info.GetIsolate(), StringView(kKeepAliveKey, sizeof kKeepAliveKey)), v8Value);
+  {% endif %}
+
+  {{attribute.v8_set_return_value}};
+}
+{% endif %}
+
 static void {{attribute.name}}AttributeGetter{{world_suffix}}(
 {%- if attribute.is_data_type_property %}
 const v8::PropertyCallbackInfo<v8::Value>& info
 {%- else %}
 const v8::FunctionCallbackInfo<v8::Value>& info
 {%- endif %}) {
   {% filter format_remove_duplicates(['ExceptionState exceptionState']) %}
   {% set define_exception_state -%}
   ExceptionState exceptionState(info.GetIsolate(), ExceptionState::GetterContext, "{{interface_name}}", "{{attribute.name}}");
   {%- endset %}
@@ skipping 452 matching lines @@
        setter_callback_for_main_world,
        cached_accessor_callback,
        wrapper_type_info,
        access_control,
        property_attribute,
        property_location(attribute),
        holder_check,
    ] %}
 {{'{'}}{{attribute_configuration_list | join(', ')}}{{'}'}}
 {%- endmacro %}