Mojo C++ bindings: add StringTraits and ArrayTraits for STL types.

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

-// Copyright 2016 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_ARRAY_TRAITS_WTF_H_
-#define MOJO_PUBLIC_CPP_BINDINGS_LIB_ARRAY_TRAITS_WTF_H_
-
-#include "mojo/public/cpp/bindings/array_traits.h"
-#include "mojo/public/cpp/bindings/wtf_array.h"
-
-namespace mojo {
-
-template <typename U>
-struct ArrayTraits<WTFArray<U>> {
-  using Element = U;
-
-  static bool IsNull(const WTFArray<U>& input) { return input.is_null(); }
-  static void SetToNull(WTFArray<U>* output) { *output = nullptr; }
-
-  static size_t GetSize(const WTFArray<U>& input) { return input.size(); }
-
-  static U* GetData(WTFArray<U>& input) { return &input.front(); }
-
-  static const U* GetData(const WTFArray<U>& input) { return &input.front(); }
-
-  static U& GetAt(WTFArray<U>& input, size_t index) { return input[index]; }
-
-  static const U& GetAt(const WTFArray<U>& input, size_t index) {
-    return input[index];
-  }
-
-  static void Resize(WTFArray<U>& input, size_t size) { input.resize(size); }
-};
-
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_ARRAY_TRAITS_WTF_H_