Cleanup: Get rid of OS_WIN/OS_POSIX ifdefs from MojoApplication

ipc/ipc_channel_handle.h

 // Copyright (c) 2012 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_HANDLE_H_
 #define IPC_IPC_CHANNEL_HANDLE_H_
 
 #include <string>
 
+#include "base/files/platform_file.h"
 #include "build/build_config.h"
 
 #if defined(OS_POSIX)
 #include "base/file_descriptor_posix.h"
 #elif defined(OS_WIN)
 #include <windows.h>
 #endif  // defined (OS_WIN)
 
 // On Windows, any process can create an IPC channel and others can fetch
 // it by name.  We pass around the channel names over IPC.
@@ skipping 24 matching lines @@
 #if defined(OS_WIN)
   explicit ChannelHandle(HANDLE h) : pipe(h) {}
 #elif defined(OS_POSIX)
   ChannelHandle(const std::string& n, const base::FileDescriptor& s)
       : name(n), socket(s) {}
 #endif  // defined(OS_POSIX)
 
   std::string name;
 #if defined(OS_POSIX)
   base::FileDescriptor socket;
+
+  base::PlatformFile platform_file() const { return socket.fd; }
 #elif defined(OS_WIN)
   // A simple container to automatically initialize pipe handle
   struct PipeHandle {
     PipeHandle() : handle(NULL) {}
     PipeHandle(HANDLE h) : handle(h) {}
     HANDLE handle;
   };
   PipeHandle pipe;
+
+  base::PlatformFile platform_file() const { return pipe.handle; }
 #endif  // defined (OS_WIN)
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_CHANNEL_HANDLE_H_