[mojo-bindings] Support reuse of native enum classes

components/mus/public/interfaces/compositor_frame.mojom

 // 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.
 
 module mus.mojom;
 
 import "ui/mojo/geometry/geometry.mojom";
 import "components/mus/public/interfaces/quads.mojom";
 
-enum ResourceFormat {
-  RGBA_8888,
-  RGBA_4444,
-  BGRA_8888,
-  ALPHA_8,
-  LUMINANCE_8,
-  RGB_565,
-  ETC1,
-};
+// See src/cc/resources/resource_format.h
+[Native=True]
+enum ResourceFormat;
 
 // See src/gpu/command_buffer/common/constants.h
-enum CommandBufferNamespace {
-  INVALID = -1,
-
-  GPU_IO,
-  IN_PROCESS,
-  MOJO,
-  MOJO_LOCAL,
-  OLD_SYNC_POINTS,
-
-  NUM_COMMAND_BUFFER_NAMESPACES
-};
+[Native=True]
+enum CommandBufferNamespace;
 
 // See src/gpu/command_buffer/common/sync_token.h
 struct SyncToken {
   bool verified_flush;
   CommandBufferNamespace namespace_id;
   int32 extra_data_field;
   uint64 command_buffer_id;
   uint64 release_count;
 };
 
@@ skipping 52 matching lines @@
 interface Surface {
   // After the submitted frame is drawn for the first time, the receiver will
   // respond to the SubmitFrame message. Clients should use this acknowledgement
   // to ratelimit frame submissions.
   SubmitCompositorFrame(CompositorFrame frame) => ();
 };
 
 interface SurfaceClient {
   ReturnResources(array<ReturnedResource> resources);
 };