Add mojo structs for ScopedFD and ScopedHandle.

mojo/common/common_custom_types_struct_traits.h

Index: mojo/common/common_custom_types_struct_traits.h
diff --git a/mojo/common/common_custom_types_struct_traits.h b/mojo/common/common_custom_types_struct_traits.h
index c45ab90ca2b494ba1cc2417c728357e145636d73..25a7d64d633c44c3e945c1ea9b064d244875f340 100644
--- a/mojo/common/common_custom_types_struct_traits.h
+++ b/mojo/common/common_custom_types_struct_traits.h
@@ -11,11 +11,21 @@
 #include "base/version.h"
 #include "mojo/common/file.mojom-shared.h"
 #include "mojo/common/mojo_common_export.h"
+#include "mojo/common/platform_handle.h"
+#include "mojo/common/platform_handle.mojom-shared.h"
 #include "mojo/common/string16.mojom-shared.h"
 #include "mojo/common/time.mojom-shared.h"
 #include "mojo/common/unguessable_token.mojom-shared.h"
 #include "mojo/common/version.mojom-shared.h"
 
+#if defined(OS_POSIX)
+#include "mojo/common/common_custom_types_struct_traits_posix.h"
+#endif
+
+#if defined(OS_WIN)
+#include "mojo/common/common_custom_types_struct_traits_win.h"
+#endif
+
 namespace mojo {
 
 template <>
@@ -83,6 +93,23 @@ struct StructTraits<common::mojom::FileDataView, base::File> {
   static bool Read(common::mojom::FileDataView data, base::File* file);
 };
 
+template <typename DataView>
+struct StructTraits<DataView, common::InvalidTypemappedType> {
+  static bool IsNull(const common::InvalidTypemappedType& unused) {
+    return true;
+  }
+
+  static void SetToNull(common::InvalidTypemappedType* unused) {}
+
+  static mojo::ScopedHandle wrapped_handle(
+      const common::InvalidTypemappedType& unused) {
+    return mojo::ScopedHandle();
+  }
+  static bool Read(DataView data, common::InvalidTypemappedType* unused) {
+    return false;
+  }
+};
+
 }  // namespace mojo
 
 #endif  // MOJO_COMMON_COMMON_CUSTOM_TYPES_STRUCT_TRAITS_H_