Mojo C++ bindings: add a new mode to generator to use native STL/WTF types

mojo/public/cpp/bindings/native_enum.h

Index: mojo/public/cpp/bindings/native_enum.h
diff --git a/mojo/public/cpp/bindings/native_enum.h b/mojo/public/cpp/bindings/native_enum.h
index 140045e4a2c61a7b267a7d606d9f37e93c307eb4..08b43b78bf9277da9b74de1dc064be6d89e6f527 100644
--- a/mojo/public/cpp/bindings/native_enum.h
+++ b/mojo/public/cpp/bindings/native_enum.h
@@ -5,6 +5,9 @@
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_NATIVE_ENUM_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_NATIVE_ENUM_H_
 
+#include <functional>
+
+#include "mojo/public/cpp/bindings/lib/bindings_internal.h"
 #include "mojo/public/cpp/bindings/lib/native_enum_data.h"
 
 namespace mojo {
@@ -14,4 +17,12 @@ enum class NativeEnum : int32_t {};
 
 }  // namespace mojo
 
+namespace std {
+
+template <>
+struct hash<mojo::NativeEnum>
+    : public mojo::internal::EnumHashImpl<mojo::NativeEnum> {};
+
+}  // namespace std
+
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_NATIVE_ENUM_H_