Switch to standard integer types in mojo/.

mojo/platform_handle/platform_handle_private_thunks.cc

 // Copyright 2015 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/platform_handle/platform_handle_private_thunks.h"
 
 #include <assert.h>
+#include <stddef.h>
 
 #if defined(WIN32)
 #define THUNK_EXPORT __declspec(dllexport)
 #else
 #define THUNK_EXPORT __attribute__((visibility("default")))
 #endif
 
 extern "C" {
 
 static MojoPlatformHandlePrivateThunks g_thunks = {0};
@@ skipping 11 matching lines @@
 }
 
 extern "C" THUNK_EXPORT size_t MojoSetPlatformHandlePrivateThunks(
     const MojoPlatformHandlePrivateThunks* thunks) {
   if (thunks->size >= sizeof(g_thunks))
     g_thunks = *thunks;
   return sizeof(g_thunks);
 }
 
 }  // extern "C"