[mojo] Support native types with mojom wire format

mojo/public/tools/bindings/generators/mojom_cpp_generator.py

Index: mojo/public/tools/bindings/generators/mojom_cpp_generator.py
diff --git a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
index 856ae0d7d32c1f79999af3130b0cfcc9fc9b08a8..0733e1a8e050e6b69691d879fdd14766db8e7482 100644
--- a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
+++ b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
@@ -132,6 +132,8 @@ def GetCppPodType(kind):
 def GetCppArrayArgWrapperType(kind):
   if mojom.IsStructKind(kind) and kind.native_only:
     raise Exception("Cannot serialize containers of native-only types yet!")
+  if IsTypemappedKind(kind):
+    raise Exception("Cannot serialize containers of typemapped structs yet!")
   if mojom.IsEnumKind(kind):
     return GetNameForKind(kind)
   if mojom.IsStructKind(kind) or mojom.IsUnionKind(kind):