Switch to standard integer types in mojo/.

mojo/edk/embedder/platform_channel_pair_posix_unittest.cc

 // 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.
 
 #include "mojo/edk/embedder/platform_channel_pair.h"
 
 #include <errno.h>
 #include <poll.h>
 #include <signal.h>
+#include <stddef.h>
 #include <stdio.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <unistd.h>
 #include <deque>
 #include <utility>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
@@ skipping 231 matching lines @@
     char read_buf[100];
     size_t bytes_read = fread(read_buf, 1, sizeof(read_buf), fp.get());
     EXPECT_EQ(file_contents.size(), bytes_read);
     EXPECT_EQ(file_contents, std::string(read_buf, bytes_read));
   }
 }
 
 }  // namespace
 }  // namespace edk
 }  // namespace mojo