cros_update: Migrate to chromite

This is mostly uses the cros_update files in the chromite.

BUG=chromium:1003986
TEST=./devserver_integration_test.py

Cq-Depend: chromium:1866027
Change-Id: Id9c3f6e4c6b8e08889ec96942f37f3e084380e9a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/1894676
Tested-by: Amin Hassani <ahassani@chromium.org>
Tested-by: Achuith Bhandarkar <achuith@chromium.org>
Commit-Queue: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/health_checker.py b/health_checker.py
index d978fdb..5d9ce20 100644
--- a/health_checker.py
+++ b/health_checker.py
@@ -15,26 +15,12 @@
 import time
 
 import cherrypy  # pylint: disable=import-error
-
-import cros_update_progress
+import psutil  # pylint: disable=import-error
 
 import setup_chromite  # pylint: disable=unused-import
+from chromite.lib import cros_update_progress
 from chromite.lib.xbuddy import cherrypy_log_util
 
-try:
-  import psutil
-except ImportError:
-  # Ignore psutil import failure. This is for backwards compatibility, so
-  # "cros flash" can still update duts with build without psutil installed.
-  # The reason is that, during cros flash, local devserver code is copied over
-  # to DUT, and devserver will be running inside DUT to stage the build.
-  psutil = None
-except OSError:
-  # Ignore error like following. psutil may not work properly in builder. Ignore
-  # the error as load information of devserver is not used in builder.
-  # OSError: [Errno 2] No such file or directory: '/dev/pts/0'
-  psutil = None
-
 
 def _Log(message, *args):
   """Module-local log function."""