Added SyncToken command buffer trait to help with IPC messages.

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.
 group("common") {
   if (is_component_build) {
@@ skipping 26 matching lines @@
     "gles2_cmd_format.h",
     "gles2_cmd_format_autogen.h",
     "gles2_cmd_ids.h",
     "gles2_cmd_ids_autogen.h",
     "id_allocator.cc",
     "id_allocator.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 = [
     ":gles2_utils",
     "//base",
   ]
 }
 
 component("gles2_utils") {
   sources = [
     "gles2_cmd_utils.cc",
     "gles2_cmd_utils.h",
     "gles2_utils_export.h",
   ]
 
   defines = [ "GLES2_UTILS_IMPLEMENTATION" ]
 
   deps = [
     "//base",
   ]
 
   all_dependent_configs = [ "//third_party/khronos:khronos_headers" ]
 }