On Linux, move the passing of filedescriptors to a dedicated socketpair().

ipc/ipc_channel_posix.h

 // Copyright (c) 2008 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 IPC_IPC_CHANNEL_POSIX_H_
 #define IPC_IPC_CHANNEL_POSIX_H_
 
 #include "ipc/ipc_channel.h"
 
 #include <sys/socket.h>  // for CMSG macros
@@ skipping 65 matching lines @@
   // unused otherwise.
   int server_listen_pipe_;
 
   // The pipe used for communication.
   int pipe_;
 
   // For a server, the client end of our socketpair() -- the other end of our
   // pipe_ that is passed to the client.
   int client_pipe_;
 
+#if defined(OS_LINUX)
+  // Linux uses a dedicated socketpair() for passing file descriptors.
+  int fd_pipe_;
+  int remote_fd_pipe_;
+#endif
+
   // The "name" of our pipe.  On Windows this is the global identifier for
   // the pipe.  On POSIX it's used as a key in a local map of file descriptors.
   std::string pipe_name_;
 
   Listener* listener_;
 
   // Messages to be sent are queued here.
   std::queue<Message*> output_queue_;
 
   // We read from the pipe into this buffer
@@ skipping 30 matching lines @@
   bool processing_incoming_;
 
   ScopedRunnableMethodFactory<ChannelImpl> factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ChannelImpl);
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_CHANNEL_POSIX_H_