Remove Windows support from the EDK.

mojo/edk/embedder/platform_handle.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 "mojo/edk/embedder/platform_handle.h"
 
-#include "build/build_config.h"
-#if defined(OS_POSIX)
 #include <unistd.h>
-#elif defined(OS_WIN)
-#include <windows.h>
-#else
-#error "Platform not yet supported."
-#endif
 
 #include "base/logging.h"
 
 namespace mojo {
 namespace embedder {
 
 void PlatformHandle::CloseIfNecessary() {
   if (!is_valid())
     return;
 
-#if defined(OS_POSIX)
   bool success = (close(fd) == 0);
   DPCHECK(success);
   fd = -1;
-#elif defined(OS_WIN)
-  bool success = !!CloseHandle(handle);
-  DPCHECK(success);
-  handle = INVALID_HANDLE_VALUE;
-#else
-#error "Platform not yet supported."
-#endif
 }
 
 }  // namespace embedder
 }  // namespace mojo