Adds thunks for getting platform handles

mojo/platform_handle/platform_handle_thunks.h

+// Copyright 2015 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_PLATFORM_HANDLE_PLATFORM_HANDLE_THUNKS_H_
+#define MOJO_PLATFORM_HANDLE_PLATFORM_HANDLE_THUNKS_H_
+
+#include <stddef.h>
+
+#include "mojo/platform_handle/platform_handle_functions.h"
+
+#pragma pack(push, 8)
+struct MojoPlatformHandleThunks {

[viettrungluu, 2015/05/01 17:05:51]

You might want to call this "MojoPlatformHandlePrivateThunks", to make it clear
that this is not part of the public API for standard, untrusted apps.

[sky, 2015/05/01 17:18:45]

Done.

+  size_t size;  // Should be set to sizeof(PlatformHandleThunks).
+  bool (*CreatePlatformHandleWrapper)(MojoPlatformHandle, MojoHandle*);
+  bool (*ExtractPlatformHandle)(MojoHandle, MojoPlatformHandle*);
+};
+#pragma pack(pop)
+
+inline MojoPlatformHandleThunks MojoMakePlatformHandleThunks() {
+  MojoPlatformHandleThunks system_thunks = {sizeof(MojoPlatformHandleThunks),
+                                            MojoCreatePlatformHandleWrapper,
+                                            MojoExtractPlatformHandle};
+  return system_thunks;
+}
+
+typedef size_t (*MojoSetPlatformHandleThunksFn)(
+    const struct MojoPlatformHandleThunks* thunks);
+
+#endif  // MOJO_PLATFORM_HANDLE_PLATFORM_HANDLE_THUNKS_H_