Fix net_unittests build errors when enable_bidirectional_stream is set.

net/net.gyp

 # Copyright 2013 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.
 
 {
   'variables': {
     'chromium_code': 1,
     'linux_link_kerberos%': 0,
     'conditions': [
       ['chromeos==1 or embedded==1 or OS=="ios"', {
@@ skipping 271 matching lines @@
             ],
             'sources!': [
               'url_request/url_request_ftp_job_unittest.cc',
             ],
           },
         ],
         [ 'enable_bidirectional_stream!=1', {
             'sources!': [
               'http/bidirectional_stream_unittest.cc',
             ],
-          },
+          }, { # else
+           'defines': [
+              'ENABLE_BIDIRECTIONAL_STREAM',
+            ],
+          }
         ],
         [ 'enable_built_in_dns!=1', {
             'sources!': [
               'dns/address_sorter_posix_unittest.cc',
               'dns/address_sorter_unittest.cc',
             ],
           },
         ],
         [ 'use_v8_in_net==1', {
             'dependencies': [
@@ skipping 1399 matching lines @@
             '../build/isolate.gypi',
           ],
           'sources': [
             'net_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }