Implement cc::SurfaceId StructTraits

components/mus/public/interfaces/surface_id.mojom

-// Copyright 2014 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.
-
-module mus.mojom;
-
-// A surface ID is composed of three parts: a namespace, a local ID, and a
-// nonce. The local part and nonce are allocated by the client using any scheme
-// that avoids duplicates and makes IDs unguessable respectively. The namespace
-// is allocated by the service and will be different for each client.
-//
-// The special id_namespace value 0 is equivalent to the namespace of the
-// client. This can be used to create, destroy and submit frames to
-// surfaces before learning the namespace and to reference other surfaces
-// owned by the same client. The actual id namespace must be used to pass
-// surface ids to other clients for them to reference.
-struct SurfaceId {
-  // A service allocated ID identifying a client.
-  uint32 id_namespace;
-
-  // An identifier allocated by the client uniquely identifying a surface within
-  // a client process.
-  uint32 local_id;
-
-  // A cryptographically secure random int chosen to make the SurfaceId
-  // unguessable by other clients.
-  uint64 nonce;
-};