Hook up GL Command buffer on Windows too

mojo/examples/sample_app/sample_app.cc

 // Copyright 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.
 
 #include <stdio.h>
 
 #include "mojo/public/system/core.h"
 #include "mojo/public/system/macros.h"
-#include "mojo/system/core_impl.h"
 
-#if defined(OS_WIN)
+#if defined(WIN32)
 #if !defined(CDECL)
 #define CDECL __cdecl
 #endif
 #define SAMPLE_APP_EXPORT __declspec(dllexport)
 #else
 #define CDECL
 #define SAMPLE_APP_EXPORT __attribute__((visibility("default")))
 #endif
 
 char* ReadStringFromPipe(mojo::Handle pipe) {
@@ skipping 45 matching lines @@
   mojo::Handle pipe_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(SampleMessageWaiter);
 };
 
 extern "C" SAMPLE_APP_EXPORT MojoResult CDECL MojoMain(
     mojo::Handle pipe) {
   SampleMessageWaiter(pipe).WaitAndRead();
   return MOJO_RESULT_OK;
 }