Revert of mojo: Convert gles2 to the new thunking system

mojo/public/gles2/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.
 
 config("gles2_config") {
   defines = [ "GLES2_USE_MOJO" ]
 }
 
 shared_library("gles2") {
   output_name = "mojo_gles2"
 
   defines = [
     "MOJO_GLES2_IMPLEMENTATION",
   ]
 
   configs += [
     ":gles2_config",
     "//third_party/khronos:khronos_headers",
   ]
   direct_dependent_configs = [ ":gles2_config" ]
 
   sources = [
     "../c/gles2/gles2.h",
     "../c/gles2/gles2_export.h",
-    "../platform/native/gles2_thunks.cc",
-    "../platform/native/gles2_thunks.h",
-    "gles2_interface.h",
+    "gles2_private.cc",
+    "gles2_private.h",
   ]
 
   if (is_mac) {
     # TODO(GYP): Make it a run-path dependent library.
     # 'DYLIB_INSTALL_NAME_BASE': '@loader_path',
   }
 }