Add a stub implementation of khronos_glcts_test to the GN build.

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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 262 matching lines @@
       "//gin:gin_unittests",
       "//google_apis:google_apis_unittests",
       "//google_apis/gcm:mcs_probe",
       "//gpu:angle_unittests",
       "//gpu:gl_tests",
 
       # TODO(GYP): Remove this when the gles2 tests work
       "//gpu/command_buffer/client:gles2_implementation_no_check",
 
       "//gpu:gpu_perftests",
+      "//gpu/khronos_glcts_support:khronos_glcts_test",  # TODO(GYP) crbug.com/471903 to make this complete.
       "//ipc:ipc_perftests",
       "//media:ffmpeg_regression_tests",  # TODO(GYP) this should be conditional on media_use_ffmpeg
       "//media:media_perftests",
       "//media/cast:cast_benchmarks",
       "//media/cast:generate_barcode_video",
       "//media/cast:generate_timecode_audio",
       "//media/cast:tap_proxy",
       "//mojo/application",
       "//net:crash_cache",
       "//net:crl_set_dump",
@@ skipping 363 matching lines @@
 
       # Note:
       # (*) Fails but failures match GYP build at time of testing.
     ]
 
     if (enable_nacl) {
       deps += [ "//components/nacl:nacl_loader_unittests" ]  # PASSES 3/28/2015
     }
   }
 }