Enable OWNERS file enforcement in depot_tools

R=chase@chromium.org,maruel@chromium.org
Review URL: http://codereview.chromium.org/6676058

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@78632 0039d316-1c4b-4281-b951-d872f2087c98

PRESUBMIT.py

@@ -32,11 +32,7 @@ def CommonChecks(input_api, output_api):
       # Return right away because it needs to be fixed first.
       return output
 
-  # TODO(dpranke): uncomment and enable :).
-  #
-  # output.extend(input_api.canned_checks.CheckOwners(
-  #     input_api,
-  #     output_api))
+  output.extend(input_api.canned_checks.CheckOwners(input_api, output_api))
 
   output.extend(input_api.canned_checks.RunPythonUnitTests(
       input_api,