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

gpu/BUILD.gn

 # 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.
 
 # GYP-to-GN project mappings:
 #
 #  gpu.gyp:command_buffer_client => //gpu/command_buffer/client
 #
 #  gpu.gyp:command_buffer_common => //gpu/command_buffer/common
 #
@@ skipping 214 matching lines @@
     "command_buffer/client/vertex_array_object_manager_unittest.cc",
     "command_buffer/common/bitfield_helpers_test.cc",
     "command_buffer/common/command_buffer_mock.cc",
     "command_buffer/common/command_buffer_mock.h",
     "command_buffer/common/command_buffer_shared_test.cc",
     "command_buffer/common/debug_marker_manager_unittest.cc",
     "command_buffer/common/gles2_cmd_format_test.cc",
     "command_buffer/common/gles2_cmd_format_test_autogen.h",
     "command_buffer/common/gles2_cmd_utils_unittest.cc",
     "command_buffer/common/id_allocator_test.cc",
+    "command_buffer/common/id_type_unittest.cc",
     "command_buffer/common/unittest_main.cc",
     "command_buffer/service/buffer_manager_unittest.cc",
     "command_buffer/service/cmd_parser_test.cc",
     "command_buffer/service/command_buffer_service_unittest.cc",
     "command_buffer/service/common_decoder_unittest.cc",
     "command_buffer/service/context_group_unittest.cc",
     "command_buffer/service/context_state_unittest.cc",
     "command_buffer/service/feature_info_unittest.cc",
     "command_buffer/service/framebuffer_manager_unittest.cc",
     "command_buffer/service/gl_context_mock.cc",
@@ skipping 99 matching lines @@
     "//base",
     "//base/test:test_support",
     "//gpu/command_buffer/service",
     "//testing/gmock",
     "//testing/gtest",
     "//testing/perf",
     "//ui/gfx/geometry",
     "//ui/gl",
   ]
 }