[recipes] Remove build environment vars from default_env

infra/bots/recipe_modules/flavor/gn_flavor.py

 # Copyright 2016 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 default_flavor
 
 """GN flavor utils, used for building Skia with GN."""
 class GNFlavorUtils(default_flavor.DefaultFlavorUtils):
-  def compile(self, target):
+  def compile(self, target, **kwargs):
     """Build Skia with GN."""
     # Get the gn executable.
     fetch_gn = self.m.vars.skia_dir.join('bin', 'fetch-gn')
     self.m.run(self.m.step, 'fetch-gn',
                cmd=[fetch_gn],
-               cwd=self.m.vars.skia_dir)
+               cwd=self.m.vars.skia_dir,
+               **kwargs)
 
     is_debug = 'is_debug=true'
     if self.m.vars.configuration != 'Debug':
       is_debug = 'is_debug=false'
     gn_args = [is_debug]
 
     is_clang = 'Clang' in self.m.vars.builder_name
     is_gcc   = 'GCC'   in self.m.vars.builder_name
 
     cc, cxx = 'cc', 'c++'
@@ skipping 11 matching lines @@
         cc, cxx = '%s %s' % (cc, stifle), '%s %s' % (cxx, stifle)
 
     gn_args += [ 'cc="%s"' % cc, 'cxx="%s"' % cxx ]
 
     # Run gn gen.
     gn_exe = 'gn'
     if self.m.platform.is_win:
       gn_exe = 'gn.exe'
     gn_gen = [gn_exe, 'gen', self.out_dir, '--args=%s' % ' '.join(gn_args)]
     self.m.run(self.m.step, 'gn_gen', cmd=gn_gen,
-               cwd=self.m.vars.skia_dir)
+               cwd=self.m.vars.skia_dir, **kwargs)
 
     # Run ninja.
     ninja_cmd = ['ninja', '-C', self.out_dir]
     self.m.run(self.m.step, 'compile %s' % target,
                cmd=ninja_cmd,
-               cwd=self.m.vars.skia_dir)
+               cwd=self.m.vars.skia_dir,
+               **kwargs)