[mojo][bindings] Do not generate Serialize method for structs with

handles

This change removes generation of the Serialize() method for structs
that contain handles since such handles would not be deserialized
correctly outside of IPC sendind context.

Bug: 1147520
Change-Id: Ia9bfa29075d5610b21089bccc4f27015c83dc05c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2538370Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Oksana Zhuravlova <oksamyt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828233}

mojo/public/tools/bindings/generators/cpp_templates/wrapper_class_declaration.tmpl

@@ -69,11 +69,13 @@ class {{export_attribute}} {{struct.name}} {
 {%- set serialization_result_type = "WTF::Vector<uint8_t>"
         if for_blink else "std::vector<uint8_t>" %}
 
+{%- if not struct|contains_handles_or_interfaces %}
   template <typename UserType>
   static {{serialization_result_type}} Serialize(UserType* input) {
     return mojo::internal::SerializeImpl<
         {{struct.name}}::DataView, {{serialization_result_type}}>(input);
   }
+{%- endif %}
 
   template <typename UserType>
   static mojo::Message SerializeAsMessage(UserType* input) {

ui/base/cursor/mojom/cursor_mojom_traits_unittest.cc

@@ -17,7 +17,8 @@ namespace ui {
 namespace {
 
 bool EchoCursor(const ui::Cursor& in, ui::Cursor* out) {
-  return mojom::Cursor::Deserialize(mojom::Cursor::Serialize(&in), out);
+  return mojom::Cursor::DeserializeFromMessage(
+      mojom::Cursor::SerializeAsMessage(&in), out);
 }
 
 using CursorStructTraitsTest = testing::Test;