Swarming: Ensure depot_tools is in PATH when compiling

infra/bots/flavor/default_flavor.py

Index: infra/bots/flavor/default_flavor.py
diff --git a/infra/bots/flavor/default_flavor.py b/infra/bots/flavor/default_flavor.py
index 4d1111795db95becc48aaef679c0fc866f765950..e59887301fc0fecb720287ec9b6c85d6ace493dd 100644
--- a/infra/bots/flavor/default_flavor.py
+++ b/infra/bots/flavor/default_flavor.py
@@ -107,6 +107,9 @@ class DefaultFlavorUtils(object):
       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)