mac/linux: rework plugin channel file descriptor creation

chrome/plugin/plugin_thread.h

 // Copyright (c) 2006-2008 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 CHROME_PLUGIN_PLUGIN_THREAD_H_
 #define CHROME_PLUGIN_PLUGIN_THREAD_H_
 
 #include "base/file_path.h"
 #include "base/native_library.h"
 #include "build/build_config.h"
@@ skipping 19 matching lines @@
   static PluginThread* current();
 
  private:
   virtual void OnControlMessageReceived(const IPC::Message& msg);
 
   // Thread implementation:
   virtual void Init();
   virtual void CleanUp();
 
   // Callback for when a channel has been created.
-  // On POSIX, |socket| is the channel endpoint socket.
   void OnCreateChannel(
-#if defined(OS_POSIX)
-      base::FileDescriptor socket,
-#endif
       int process_id,
       bool off_the_record);
   void OnPluginMessage(const std::vector<uint8> &data);
 
   scoped_ptr<NotificationService> notification_service_;
 
   // The plugin module which is preloaded in Init
   base::NativeLibrary preloaded_plugin_module_;
 
   // Points to the plugin file that this process hosts.
   FilePath plugin_path_;
 
   DISALLOW_EVIL_CONSTRUCTORS(PluginThread);
 };
 
 #endif  // CHROME_PLUGIN_PLUGIN_THREAD_H_