Simplify the thunk targets since we don't support apps as components

mojo/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.
 
 import("//mojo/public/tools/bindings/mojom.gni")
 
 config("mojo_use_gles2") {
   defines = [ "MOJO_USE_GLES2_IMPL" ]
 }
 
 config("gles2_use_mojo") {
   defines = [ "GLES2_USE_MOJO" ]
 }
 
-# GYP version: mojo/mojo_base.gyp:mojo_gles2_impl
-component("gles2") {
-  output_name = "mojo_gles2_impl"
-
+source_set("gles2") {
   sources = [
     "command_buffer_client_impl.cc",
     "command_buffer_client_impl.h",
-    "gles2_impl_export.h",
     "gles2_impl.cc",
     "gles2_context.cc",
     "gles2_context.h",
   ]
 
   defines = [
     "GL_GLEXT_PROTOTYPES",
-    "MOJO_GLES2_IMPL_IMPLEMENTATION",
     "MOJO_GLES2_IMPLEMENTATION",
   ]
 
   configs += [
     ":gles2_use_mojo",
     ":mojo_use_gles2",
   ]
   public_configs = [ ":gles2_use_mojo" ]
   all_dependent_configs = [ ":mojo_use_gles2" ]
 
   deps = [
     "//base",
     "//base/third_party/dynamic_annotations",
     "//gpu/command_buffer/client",
     "//gpu/command_buffer/client:gles2_cmd_helper",
     "//gpu/command_buffer/client:gles2_implementation",
     "//gpu/command_buffer/client:gles2_interface",
     "//gpu/command_buffer/common",
     "//mojo/environment:chromium",
-    "//mojo/public/c/gles2",
-    "//mojo/public/c/system:for_component",
+    "//mojo/public/c/gles2:headers",
+    "//mojo/public/c/system",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/system",
     "//mojo/services/public/interfaces/gpu",
     "//services/gles2:lib",
   ]
 }