Fix up gles2 thunk targets a bit

mojo/public/platform/native/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.
 
 source_set("system_thunks") {
   visibility = [
     "//mojo/public/c/system:for_component",
     "//mojo/public/c/system:for_shared_library",
   ]
 
   sources = [
     "system_thunks.h",
     "system_thunks.cc",
   ]
   defines = [ "MOJO_SYSTEM_IMPLEMENTATION" ]
   deps = [ "//mojo/public/c/system" ]
 
   # The GYP target analogous to this one builds this code into a
   # static library.  When building for Android, both the GYP and GN
   # builds add --exclude-libs=ALL globally, which means that all
   # symbols in static libraries are excluded from export.  That's a
   # problem, as code outside this target needs to be able to call
   # MojoSetSystemThunks(). Therefore, the GYP target needs to specifiy
   # that all dependent targets remove that link flag. Since GN uses a
   # source_set here, this flag change is not needed.
 }
+
+# GYP version: mojo/mojo_public.gypi:mojo_gles2
+source_set("gles2_thunks") {
+  visibility = [ "//mojo/public/gles2:for_shared_library" ]
+
+  sources = [
+    "gles2_thunks.cc",
+    "gles2_thunks.h",
+    "gles2_impl_thunks.cc",
+    "gles2_impl_thunks.h",
+    "gles2_impl_chromium_texture_mailbox_thunks.cc",
+    "gles2_impl_chromium_texture_mailbox_thunks.h",
+    "gles2_impl_chromium_sync_point_thunks.cc",
+    "gles2_impl_chromium_sync_point_thunks.h",
+  ]
+
+  defines = [
+    "MOJO_GLES2_IMPLEMENTATION",
+  ]
+
+  configs += [ "//third_party/khronos:khronos_headers" ]
+
+  deps = [
+    "//mojo/public/c/gles2",
+    "//mojo/public/c/environment",
+    "//mojo/public/c/system",
+  ]
+
+  if (is_mac) {
+    # TODO(GYP): Make it a run-path dependent library.
+    # 'DYLIB_INSTALL_NAME_BASE': '@loader_path',
+  }
+}