Swarming: Ensure depot_tools is in PATH when compiling

infra/bots/flavor/default_flavor.py

 #!/usr/bin/env python
 #
 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 
 """Default flavor utils class, used for desktop bots."""
 
@@ skipping 89 matching lines @@
   def compile(self, target):
     """Build the given target."""
     # The CHROME_PATH environment variable is needed for bots that use
     # toolchains downloaded by Chrome.
     env = {}
     if sys.platform == 'win32':
       make_cmd = ['python', 'make.py']
       env['CHROME_PATH'] = self.chrome_path
       self._bot_info._run_once(self.bootstrap_win_toolchain)
     else:
+      # Ensure depot_tools is in PATH.
+      depot_tools = os.path.join('/b', 'depot_tools')
+      env['PATH'] = os.pathsep.join([depot_tools, os.environ['PATH']])
       make_cmd = ['make']
     cmd = make_cmd + [target]
     self._bot_info.run(cmd, env=env)
 
   def device_path_join(self, *args):
     """Like os.path.join(), but for paths on a connected device."""
     return os.path.join(*args)
 
   def device_path_exists(self, path):
     """Like os.path.exists(), but for paths on a connected device."""
@@ skipping 58 matching lines @@
     return DeviceDirs(
         dm_dir=os.path.join(self._bot_info.swarm_out_dir, 'dm'),
         perf_data_dir=self._bot_info.perf_data_dir,
         resource_dir=self._bot_info.resource_dir,
         images_dir=join('images'),
         skp_dir=self._bot_info.local_skp_dir,
         tmp_dir=join('tmp'))
 
   def __repr__(self):
     return '<%s object>' % self.__class__.__name__  # pragma: no cover