Add mojo structs for ScopedFD and ScopedHandle.

mojo/common/common_custom_types_struct_traits_posix.cc

Index: mojo/common/common_custom_types_struct_traits_posix.cc
diff --git a/mojo/common/common_custom_types_struct_traits_posix.cc b/mojo/common/common_custom_types_struct_traits_posix.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3319a5064952a2b69c4742e706d3a226be209c5f
--- /dev/null
+++ b/mojo/common/common_custom_types_struct_traits_posix.cc
@@ -0,0 +1,30 @@
+// 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.
+
+#include "mojo/common/common_custom_types_struct_traits_posix.h"
+
+#include "mojo/public/cpp/system/platform_handle.h"
+
+namespace mojo {
+
+mojo::ScopedHandle
+StructTraits<common::mojom::FileDescriptorDataView,
+             base::ScopedFD>::wrapped_handle(base::ScopedFD& fd) {
+  DCHECK(fd.is_valid());
+  return mojo::WrapPlatformFile(fd.release());
+}
+
+bool StructTraits<common::mojom::FileDescriptorDataView, base::ScopedFD>::Read(
+    common::mojom::FileDescriptorDataView data,
+    base::ScopedFD* fd) {
+  base::PlatformFile platform_handle = base::kInvalidPlatformFile;
+  if (mojo::UnwrapPlatformFile(data.TakeWrappedHandle(), &platform_handle) !=
+      MOJO_RESULT_OK) {
+    return false;
+  }
+  *fd = base::ScopedFD(platform_handle);
+  return true;
+}
+
+}  // namespace mojo