Mojo: Move PlatformChannelPair to its own files.

mojo/system/platform_channel_pair_posix.cc

Index: mojo/system/platform_channel_pair_posix.cc
diff --git a/mojo/system/platform_channel_posix.cc b/mojo/system/platform_channel_pair_posix.cc
similarity index 97%
rename from mojo/system/platform_channel_posix.cc
rename to mojo/system/platform_channel_pair_posix.cc
index b71428ddc966430e9076dab4ce07aa2b039aa389..f0a072b49f27d3ab3cac4a5e63b26e356f655eb1 100644
--- a/mojo/system/platform_channel_posix.cc
+++ b/mojo/system/platform_channel_pair_posix.cc
@@ -1,8 +1,8 @@
-// Copyright 2013 The Chromium Authors. All rights reserved.
+// Copyright 2014 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.
 
-#include "mojo/system/platform_channel.h"
+#include "mojo/system/platform_channel_pair.h"
 
 #include <fcntl.h>
 #include <sys/socket.h>
@@ -13,6 +13,7 @@
 #include "base/logging.h"
 #include "base/posix/global_descriptors.h"
 #include "base/strings/string_number_conversions.h"
+#include "mojo/system/platform_channel.h"
 
 namespace mojo {
 namespace system {