Move third_party/mojo/src/mojo/public to mojo/public

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

 size_t GetSerializedSize_(const {{union.name}}Ptr& input, bool inlined) {
   size_t size = 0U;
   if (!inlined) {
     size += sizeof(internal::{{union.name}}_Data);
   }
 
   if (!input)
     return size;
 
   mojo::internal::UnionAccessor<{{union.name}}> input_acc(input.get());
@@ skipping 114 matching lines @@
 {%-   endif %}
         break;
       }
 {%- endfor %}
     }
     *output = result.Pass();
   } else {
     output->reset();
   }
 }