Introducing gpu::CommandBufferId as a distinct, IdType<...>-based type.

gpu/command_buffer/common/BUILD.gn

 # Copyright (c) 2013 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.
 
 # The files here go into the "gpu" component in a component build (with
 # "command_buffer_common" just forwarding) and goes into a static library in
 # non-component build. This needs to match the GYP build which was likely an
 # attempt to make larger components to help with loading.
 import("//mojo/public/tools/bindings/mojom.gni")
 
@@ skipping 14 matching lines @@
 
   sources = [
     "bitfield_helpers.h",
     "buffer.cc",
     "buffer.h",
     "capabilities.cc",
     "capabilities.h",
     "cmd_buffer_common.cc",
     "cmd_buffer_common.h",
     "command_buffer.h",
+    "command_buffer_id.h",
     "constants.h",
     "debug_marker_manager.cc",
     "debug_marker_manager.h",
     "gles2_cmd_format.cc",
     "gles2_cmd_format.h",
     "gles2_cmd_format_autogen.h",
     "gles2_cmd_ids.h",
     "gles2_cmd_ids_autogen.h",
     "id_allocator.cc",
     "id_allocator.h",
+    "id_type.h",
     "mailbox.cc",
     "mailbox.h",
     "mailbox_holder.cc",
     "mailbox_holder.h",
+    "sync_token.cc",
     "sync_token.h",
     "thread_local.h",
     "time.h",
     "value_state.cc",
     "value_state.h",
   ]
 
   configs += [ "//gpu:gpu_implementation" ]
 
   deps = [
@@ skipping 24 matching lines @@
     "command_buffer.mojom",
     "mailbox.mojom",
     "mailbox_holder.mojom",
     "sync_token.mojom",
     "value_state.mojom",
   ]
 
   typemaps = [ "mojo.typemap" ]
   typemap_deps = [ "//gpu/ipc" ]
 }