Eliminate the 'build_ppapi_ipc_proxy_untrusted' build flag for untrusted PPAPI proxy builds.

chrome/nacl.gypi

 # 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.
 
 {
   'include': [
     '../native_client/build/untrusted.gypi',
   ],
   'target_defaults': {
     'variables': {
@@ skipping 62 matching lines @@
             '../base/base.gyp:base',
             '../ipc/ipc.gyp:ipc',
             '../ppapi/native_client/src/trusted/plugin/plugin.gyp:ppGoogleNaClPluginChrome',
             '../native_client/src/trusted/service_runtime/service_runtime.gyp:sel',
             '../native_client/src/trusted/platform_qualify/platform_qualify.gyp:platform_qual_lib',
           ],
           'conditions': [
             ['disable_nacl_untrusted==0', {
               'dependencies': [
                 '../ppapi/native_client/native_client.gyp:nacl_irt',
+                '../ppapi/native_client/native_client.gyp:nacl_ipc_irt',
               ],
             }],
           ],
           'direct_dependent_settings': {
             'defines': [
               '<@(nacl_defines)',
             ],
           },
         },
       ],
@@ skipping 102 matching lines @@
               'target_name': 'nacl_win64',
               'type': 'none',
               'sources': [],
             },
           ],
         }],
       ],
     }],
   ],
 }