[presubmit][owners] Skip owners check when Owners-Override is +1

Add support for Owners-Override label to allow trusted bots, sheriffs,
and global owners to bypass owners checks.

Bug: 1093627
Change-Id: Ie217369a67e4060807c0a12f84430e30a7c57daa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2530488Reviewed-by: Yulan Lin <yulanlin@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

presubmit_canned_checks.py

@@ -1122,10 +1122,17 @@ def CheckOwnersFormat(input_api, output_api):
 
 
 def CheckOwners(input_api, output_api, source_file_filter=None):
-  # Skip OWNERS check when Bot-Commit label is approved.
-  if (input_api.change.issue
-      and input_api.gerrit.IsBotCommitApproved(input_api.change.issue)):
-    return []
+  if input_api.change.issue:
+    # Skip OWNERS check when Bot-Commit label is approved. This label is
+    # intended for commits made by trusted bots that don't require review nor
+    # owners approval.
+    if input_api.gerrit.IsBotCommitApproved(input_api.change.issue):
+      return []
+    # Skip OWNERS check when Owners-Override label is approved. This is intended
+    # for global owners, trusted bots, and on-call sheriffs. Review is still
+    # required for these changes.
+    if input_api.gerrit.IsOwnersOverrideApproved(input_api.change.issue):
+      return []
 
   affected_files = set([f.LocalPath() for f in
       input_api.change.AffectedFiles(file_filter=source_file_filter)])

presubmit_support.py

@@ -446,6 +446,9 @@ class GerritAccessor(object):
   def IsBotCommitApproved(self, issue):
     return bool(self._GetApproversForLabel(issue, 'Bot-Commit'))
 
+  def IsOwnersOverrideApproved(self, issue):
+    return bool(self._GetApproversForLabel(issue, 'Owners-Override'))
+
   def GetChangeOwner(self, issue):
     return self.GetChangeInfo(issue)['owner']['email']
 

tests/presubmit_unittest.py

@@ -2778,6 +2778,33 @@ the current line as well!
         response=response,
         expected_output='')
 
+  def testCannedCheckOwners_OwnersOverride(self):
+    response = {
+      "owner": {"email": "john@example.com"},
+      "labels": {"Owners-Override": {
+        u'all': [
+          {
+            u'email': u'sheriff@example.com',
+            u'value': 1
+          },
+        ],
+        u'approved': {u'email': u'sheriff@example.org'},
+        u'default_value': 0,
+        u'values': {u' 0': u'No score',
+                    u'+1': u'Looks good to me'},
+      }},
+      "reviewers": {"REVIEWER": [{u'email': u'sheriff@example.com'}]},
+    }
+    self.AssertOwnersWorks(approvers=set(),
+        response=response,
+        is_committing=True,
+        expected_output='')
+
+    self.AssertOwnersWorks(approvers=set(),
+        is_committing=False,
+        response=response,
+        expected_output='')
+
   def testCannedCheckOwners_Approved(self):
     response = {
       "owner": {"email": "john@example.com"},