GN: port Valgrind bots.

infra/bots/recipe_modules/flavor/valgrind_flavor.py

 # Copyright 2014 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
+import gn_flavor
 
 
 """Utils for running under Valgrind."""
 
 
-class ValgrindFlavorUtils(default_flavor.DefaultFlavorUtils):
+class ValgrindFlavorUtils(gn_flavor.GNFlavorUtils):
   def __init__(self, m):
     super(ValgrindFlavorUtils, self).__init__(m)
     self._suppressions_file = self.m.vars.skia_dir.join(
         'tools', 'valgrind.supp')
 
   def step(self, name, cmd, **kwargs):
     new_cmd = ['valgrind', '--gen-suppressions=all', '--leak-check=full',
                '--track-origins=yes', '--error-exitcode=1', '--num-callers=40',
                '--suppressions=%s' % self._suppressions_file]
     path_to_app = self.out_dir.join(cmd[0])
     new_cmd.append(path_to_app)
     new_cmd.extend(cmd[1:])
     return self.m.run(self.m.step, name, cmd=new_cmd,
                             **kwargs)