Add enable_mdns flag

build/common.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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 623 matching lines @@
         # TODO(csharp): Remove OS!="mac" once xcode can run the isolate code
         # again.
         # NOTE: The check for disable_nacl==0 and component=="static_library"
         # can't be used here because these variables are not defined yet, but it
         # is still not supported.
         ['inside_chromium_build==1 and OS!="mac" and OS!="ios" and OS!="android" and chromeos==0', {
           'test_isolation_mode%': 'check',
         }, {
           'test_isolation_mode%': 'noop',
         }],
-        # Whether Android ARM build uses OpenMAX DL FFT.  
+        # Whether Android ARM build uses OpenMAX DL FFT.
         ['OS=="android" and target_arch=="arm" and android_webview_build==0', {
           # Currently only supported on Android ARM, without webview.
           # When enabled, this will also enable WebAudio on Android
           # ARM.  Default is disabled.
           'use_openmax_dl_fft%': 0,
         }, {
           'use_openmax_dl_fft%': 0,
         }],
       ],
 
@@ skipping 386 matching lines @@
     'sas_dll_exists': '<!(python <(DEPTH)/build/dir_exists.py <(sas_dll_path))',
     'wix_exists': '<!(python <(DEPTH)/build/dir_exists.py <(wix_path))',
 
     'windows_sdk_default_path': '<(DEPTH)/third_party/platformsdk_win8/files',
     'directx_sdk_default_path': '<(DEPTH)/third_party/directxsdk/files',
 
     # Whether we are using the rlz library or not.  Platforms like Android send
     # rlz codes for searches but do not use the library.
     'enable_rlz%': 0,
 
+    # MDNS is disabled by default.
+    'enable_mdns%' : 0,
+
     'conditions': [
       ['OS=="win" and "<!(python <(DEPTH)/build/dir_exists.py <(windows_sdk_default_path))"=="True"', {
         'windows_sdk_path%': '<(windows_sdk_default_path)',
       }, {
         'windows_sdk_path%': 'C:/Program Files (x86)/Windows Kits/8.0',
       }],
       ['OS=="win" and "<!(python <(DEPTH)/build/dir_exists.py <(directx_sdk_default_path))"=="True"', {
         'directx_sdk_path%': '<(directx_sdk_default_path)',
       }, {
         'directx_sdk_path%': '$(DXSDK_DIR)',
@@ skipping 1040 matching lines @@
       }],
       ['enable_managed_users==1', {
         'defines': ['ENABLE_MANAGED_USERS=1'],
       }],
       ['spdy_proxy_auth_origin != ""', {
         'defines': ['SPDY_PROXY_AUTH_ORIGIN="<(spdy_proxy_auth_origin)"'],
       }],
       ['spdy_proxy_auth_property != ""', {
         'defines': ['SPDY_PROXY_AUTH_PROPERTY="<(spdy_proxy_auth_property)"'],
       }],
+      ['enable_mdns==1', {
+        'defines': ['ENABLE_MDNS=1'],
+      }]
     ],  # conditions for 'target_defaults'
     'target_conditions': [
       ['enable_wexit_time_destructors==1', {
         'conditions': [
           [ 'clang==1', {
             'cflags': [
               '-Wexit-time-destructors',
             ],
             'xcode_settings': {
               'WARNING_CFLAGS': [
@@ skipping 2125 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }