Move //mojo/services/X/public/... to //mojo/services/X/... (part 3).

mojo/services/surfaces/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.
 
 [DartPackage="mojo_services"]
 module mojo;
 
 // A surface ID is composed of two parts, a local part and a namespace. The
 // local part is allocated by the client using any scheme that avoids
 // duplicates. The namespace is allocated by the service and will be different
 // for each client (aka each connection to mojo.Surface).
 //
 // 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 {
   uint32 local;
   uint32 id_namespace;
 };