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

mojo/public/cpp/bindings/lib/bindings_internal.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_INTERNAL_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_INTERNAL_H_
 
 #include <stdint.h>
 
+#include <functional>
+
+#include "base/template_util.h"
 #include "mojo/public/cpp/bindings/interface_id.h"
 #include "mojo/public/cpp/bindings/lib/template_util.h"
 #include "mojo/public/cpp/system/core.h"
 
 namespace mojo {
 
 template <typename T>
 class Array;
 
 template <typename T>
@@ skipping 288 matching lines @@
                                                 ? MojomTypeCategory::UNION
                                                 : MojomTypeCategory::STRUCT;
 };
 
 template <typename T, MojomTypeCategory categories>
 struct BelongsTo {
   static const bool value =
       static_cast<uint32_t>(MojomTypeTraits<T>::category & categories) != 0;
 };
 
+template <typename T>
+struct EnumHashImpl {
+  static_assert(std::is_enum<T>::value, "Incorrect hash function.");
+
+  size_t operator()(T input) const {
+    using UnderlyingType = typename base::underlying_type<T>::type;
+    return std::hash<UnderlyingType>()(static_cast<UnderlyingType>(input));
+  }
+};
+
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_INTERNAL_H_