Remove obsolete methods from IPC::Channel and related classes.

ipc/ipc_descriptors.h

 // Copyright (c) 2009 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_DESCRIPTORS_H_
 #define IPC_IPC_DESCRIPTORS_H_
 
 // This is a list of global descriptor keys to be used with the
 // base::GlobalDescriptors object (see base/posix/global_descriptors.h)
 enum {
-  kPrimaryIPCChannel = 0,
-  kStatsTableSharedMemFd,
-
   // The first key that can be use to register descriptors.
-  kIPCDescriptorMax
+  kIPCDescriptorMax = 0
 };
 
 #endif  // IPC_IPC_DESCRIPTORS_H_