Change the "Missing OWNERS" presubmit check to only suggest owners for missing files.

Previously we would suggest owners for the whole CL, rather than just
the files currently missing owner approval.

R=maruel@chromium.org
BUG=130978

Review URL: https://chromiumcodereview.appspot.com/23591064

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@224183 0039d316-1c4b-4281-b951-d872f2087c98

presubmit_canned_checks.py

@@ -822,7 +822,7 @@ def CheckOwners(input_api, output_api, source_file_filter=None,
         output('Missing %s for these files:\n    %s' %
                (needed, '\n    '.join(sorted(missing_files))))]
     if not input_api.is_committing:
-      suggested_owners = owners_db.reviewers_for(affected_files, owner_email)
+      suggested_owners = owners_db.reviewers_for(missing_files, owner_email)
       output_list.append(output('Suggested OWNERS:\n    %s' %
                                 ('\n    '.join(suggested_owners or []))))
     return output_list

tests/presubmit_unittest.py

@@ -2494,7 +2494,7 @@ class CannedChecksUnittest(PresubmitTestsBase):
         fake_db.files_not_covered_by(set(['foo/xyz.cc']),
             people).AndReturn(uncovered_files)
       if not is_committing and uncovered_files:
-        fake_db.reviewers_for(set(['foo/xyz.cc']),
+        fake_db.reviewers_for(set(['foo']),
             change.author_email).AndReturn(change.author_email)
 
     self.mox.ReplayAll()