code clean-up, issue crbug.com/260966 is fixed with
https://chromiumcodereview.appspot.com/19525002 from pdr

BUG=

Review URL: https://codereview.chromium.org/266443002

git-svn-id: svn://svn.chromium.org/blink/trunk@172954 bbb929c8-8fbe-4397-9dbb-9b2b20218538