Add ipc_channel_nacl to the untrusted build and fix all compile/link errors.

ppapi/ppapi_proxy_untrusted.gyp

 # 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.
 
 # This GYP file defines untrusted (NaCl) targets.  All targets in this
 # file should be conditionally depended upon via 'disable_nacl!=1' to avoid
 # requiring NaCl sources for building.
 
 {
   'includes': [
@@ skipping 184 matching lines @@
       ],
       'variables': {
         'nlib_target': 'libipc_untrusted.a',
         'build_glibc': 0,
         'build_newlib': 1,
         'include_dirs': [
           '..',
         ],
         'sources': [
           '../ipc/file_descriptor_set_posix.cc',
-#          '../ipc/ipc_channel_posix.cc',
+          '../ipc/ipc_channel.cc',
+          '../ipc/ipc_channel_nacl.cc',
           '../ipc/ipc_channel_proxy.cc',
+          '../ipc/ipc_channel_reader.cc',
           '../ipc/ipc_logging.cc',
           '../ipc/ipc_message.cc',
           '../ipc/ipc_message_utils.cc',
+          '../ipc/ipc_platform_file.cc',
           '../ipc/ipc_sync_channel.cc',
           '../ipc/ipc_sync_message.cc',
           '../ipc/ipc_sync_message_filter.cc',
         ],
         'compile_flags': [
           '-pthread',
         ],
         'link_flags': [
           '-pthread',
           '-lbase_untrusted',
@@ skipping 184 matching lines @@
 #          '-lppruntime',
           '-pthread',
           '-lgpu_untrusted',
           '-lipc_untrusted',
           '-lbase_untrusted',
         ],
       },
     },
   ],
 }