Remove unused parts of IPC::ChannelHandle.

ipc/ipc_channel_nacl.h

Index: ipc/ipc_channel_nacl.h
diff --git a/ipc/ipc_channel_nacl.h b/ipc/ipc_channel_nacl.h
index 52ff321b08816e982ab7424eb6a6a81d00c7c481..2e4d42fbe046e1508eb6b58cadf97019a9cf872a 100644
--- a/ipc/ipc_channel_nacl.h
+++ b/ipc/ipc_channel_nacl.h
@@ -72,12 +72,6 @@ class ChannelNacl : public Channel,
   // The pipe used for communication.
   int pipe_;
 
-  // 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.
-  // For NaCl, we don't actually support looking up file descriptors by name,
-  // and it's only used for debug information.
-  std::string pipe_name_;
-
   // We use a thread for reading, so that we can simply block on reading and
   // post the received data back to the main thread to be properly interleaved
   // with other tasks in the MessagePump.