chromium: run GN in the checkout directory

scripts/slave/recipe_modules/chromium/api.py

 # 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.
 
 import re
 
 from recipe_engine import recipe_api
 from recipe_engine import util as recipe_util
 
 class TestLauncherFilterFileInputPlaceholder(recipe_util.InputPlaceholder):
@@ skipping 508 matching lines @@
   def run_gyp_chromium(self): # pragma: no cover
     gyp_chromium_path = self.m.path['checkout'].join('build', 'gyp_chromium.py')
     env = self.get_env()
     env.update(self.c.gyp_env.as_jsonish())
     self.m.python(name='gyp_chromium', script=gyp_chromium_path, env=env);
 
   def run_gn(self, use_goma=False, gn_path=None, build_dir=None, **kwargs):
     if not gn_path:
       gn_path = self.m.depot_tools.gn_py_path
 
+    kwargs.setdefault('cwd', self.m.path['checkout'])
+
     gn_args = list(self.c.gn_args)
 
     # TODO(dpranke): Figure out if we should use the '_x64' thing to
     # consistent w/ GYP, or drop it to be consistent w/ the other platforms.
     build_dir = build_dir or '//out/%s' % self.c.build_config_fs
 
     if self.c.BUILD_CONFIG == 'Debug':
       gn_args.append('is_debug=true')
     if self.c.BUILD_CONFIG == 'Release':
       gn_args.append('is_debug=false')
@@ skipping 250 matching lines @@
       }))
 
   def get_annotate_by_test_name(self, test_name):
     return 'graphing'
 
   def download_lto_plugin(self):
     return self.m.python(
         name='download LTO plugin',
         script=self.m.path['checkout'].join(
             'build', 'download_gold_plugin.py'))