utils/metrics: Move to lib

utils/metrics depends on chromite.lib, and is written such that it
contains logic a little too coupled to CrOS/chromite implementation
detials to qualify for utils.

BUG=b:223433932
TEST=run_tests, CQ

Change-Id: Ia9a21e4f97b42e13f2443c8007412ef31b9d80af
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3595160
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Alex Klein <saklein@chromium.org>
Tested-by: Alex Klein <saklein@chromium.org>
diff --git a/api/controller/sysroot.py b/api/controller/sysroot.py
index 25860f5..ac8852d 100644
--- a/api/controller/sysroot.py
+++ b/api/controller/sysroot.py
@@ -18,11 +18,11 @@
 from chromite.lib import chroot_lib
 from chromite.lib import cros_build_lib
 from chromite.lib import goma_lib
+from chromite.lib import metrics_lib
 from chromite.lib import osutils
 from chromite.lib import portage_util
 from chromite.lib import sysroot_lib
 from chromite.service import sysroot
-from chromite.utils import metrics
 
 
 _ACCEPTED_LICENSES = '@CHROMEOS'
@@ -235,7 +235,7 @@
 @validate.require_each('packages', ['category', 'package_name'])
 @validate.require_each('use_flags', ['flag'])
 @validate.validation_complete
-@metrics.collect_metrics
+@metrics_lib.collect_metrics
 def InstallPackages(input_proto, output_proto, _config):
   """Install packages into a sysroot, building as necessary and permitted."""
   compile_source = (