Use ninja as the default GYP generator on FreeBSD.

build/gyp_chromium

 #!/usr/bin/env python
 
 # 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 script is wrapper for Chromium that adds some support for how GYP
 # is invoked by Chromium beyond what can be done in the gclient hooks.
 
 import glob
@@ skipping 506 matching lines @@
   if 'make' in os.environ.get('GYP_GENERATORS', ''):
     print 'Error: make gyp generator not supported (check GYP_GENERATORS).'
     sys.exit(1)
 
   # Default to ninja on linux and windows, but only if no generator has
   # explicitly been set.
   # Also default to ninja on mac, but only when not building chrome/ios.
   # . -f / --format has precedence over the env var, no need to check for it
   # . set the env var only if it hasn't been set yet
   # . chromium.gyp_env has been applied to os.environ at this point already
-  if sys.platform.startswith('linux') and not os.environ.get('GYP_GENERATORS'):
-    os.environ['GYP_GENERATORS'] = 'ninja'
-  if sys.platform.startswith('win') and not os.environ.get('GYP_GENERATORS'):
+  if sys.platform.startswith(('linux', 'win', 'freebsd')) and \
+      not os.environ.get('GYP_GENERATORS'):
     os.environ['GYP_GENERATORS'] = 'ninja'
   elif sys.platform == 'darwin' and not os.environ.get('GYP_GENERATORS') and \
       not 'OS=ios' in os.environ.get('GYP_DEFINES', []):
     os.environ['GYP_GENERATORS'] = 'ninja'
 
   vs2013_runtime_dll_dirs = DownloadVsToolChain()
 
   # If CHROMIUM_GYP_SYNTAX_CHECK is set to 1, it will invoke gyp with --check
   # to enfore syntax checking.
   syntax_check = os.environ.get('CHROMIUM_GYP_SYNTAX_CHECK')
@@ skipping 30 matching lines @@
   print 'Running build/landmines.py...'
   subprocess.check_call(
       [sys.executable, os.path.join(script_dir, 'landmines.py')])
 
   if vs2013_runtime_dll_dirs:
     x64_runtime, x86_runtime = vs2013_runtime_dll_dirs
     CopyVsRuntimeDlls(os.path.join(chrome_src, GetOutputDirectory()),
                       (x86_runtime, x64_runtime))
 
   sys.exit(gyp_rc)