gpu: Convert egl_main_native target to GN build.

gpu/gles2_conform_support/gles2_conform_support.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'chromium_code': 1,
     # These are defined here because we want to be able to compile them on
     # the buildbots without needed the OpenGL ES 2.0 conformance tests
     # which are not open source.
@@ skipping 43 matching lines @@
         'egl/surface.h',
       ],
       'defines': [
         'EGLAPI=',
         'EGLAPIENTRY=',
       ],
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
     },
     {
+      # GN version: //gpu/gles2_conform_support/native
       'target_name': 'egl_main_native',
       'type': 'static_library',
       'dependencies': [
         'egl_native',
         '../../third_party/khronos/khronos.gyp:khronos_headers',
       ],
       'sources': [
         '<@(bootstrap_sources_native)',
       ],
       'defines': [
@@ skipping 46 matching lines @@
         'EGLAPI=',
         'EGLAPIENTRY=',
       ],
       'sources': [
         '<@(bootstrap_sources_native)',
         'gles2_conform_support.c'
       ],
     },
   ],
 }