Fix build break for chrome os.

chrome/browser/chromeos/pipe_reader.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_PIPE_READER_H_
 #define CHROME_BROWSER_CHROMEOS_PIPE_READER_H_
 
 #include <fcntl.h>
+#include <stdio.h>
 #include <string>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include "base/basictypes.h"
 
 // Given a named pipe, this class reads data from it and returns it as a string.
 // Currently, we are sending login cookies from the Chrome OS login manager to
 // Chrome over a named Unix pipe.  We want to replace this with DBus, but
@@ skipping 22 matching lines @@
   PipeReader() : pipe_(NULL) {}
 
  private:
   FILE *pipe_;
   std::string pipe_name_;
 
   DISALLOW_COPY_AND_ASSIGN(PipeReader);
 };
 
 #endif  // CHROME_BROWSER_CHROMEOS_PIPE_READER_H_