[bindings] Introduce PostMessage extended keyword

Source/bindings/templates/methods.cpp

Index: Source/bindings/templates/methods.cpp
diff --git a/Source/bindings/templates/methods.cpp b/Source/bindings/templates/methods.cpp
index bec96edb174c10a2f3f85a8733cc9d252b4e4f78..50c344af3ab500a04f7a3b067982e12718fdeff7 100644
--- a/Source/bindings/templates/methods.cpp
+++ b/Source/bindings/templates/methods.cpp
@@ -472,6 +472,8 @@ static void {{method.name}}MethodCallback{{world_suffix}}(const v8::FunctionCall
     {% endif %}
     {% if method.is_custom %}
     {{v8_class}}::{{method.name}}MethodCustom(info);
+    {% elif method.is_post_message %}
+    postMessageMethodCommon("{{interface_name}}", {{v8_class}}::toImpl(info.Holder()), info);
     {% else %}
     {{cpp_class_or_partial}}V8Internal::{{method.name}}Method{{world_suffix}}(info);
     {% endif %}