Mojo C++ bindings: make String16 and gfx::Size available in Blink

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 82e5a8a7a9a5b285b8937b9a77279d7e58fd6879..6a0a659a722702429d55fc0a6f7b327183e2dcd8 100644
--- a/mojo/common/common_custom_types_struct_traits.h
+++ b/mojo/common/common_custom_types_struct_traits.h
@@ -5,6 +5,7 @@
 #ifndef MOJO_COMMON_COMMON_CUSTOM_TYPES_STRUCT_TRAITS_H_
 #define MOJO_COMMON_COMMON_CUSTOM_TYPES_STRUCT_TRAITS_H_
 
+#include "base/strings/utf_string_conversions.h"
 #include "base/unguessable_token.h"
 #include "base/version.h"
 #include "mojo/common/common_custom_types.mojom-shared.h"
@@ -13,6 +14,13 @@
 namespace mojo {
 
 template <>
+struct StructTraits<mojo::common::mojom::String16DataView, base::string16> {
+  static std::vector<uint16_t> data(const base::string16& str);
+  static bool Read(mojo::common::mojom::String16DataView data,
+                   base::string16* out);
+};
+
+template <>
 struct StructTraits<mojo::common::mojom::VersionDataView, base::Version> {
   static bool IsNull(const base::Version& version) {
       return !version.IsValid();