Remove unused imports

After the https://codereview.chromium.org/14668003 refactor both of
these are unused.

BUG=330137

Review URL: https://codereview.chromium.org/116073005

git-svn-id: svn://svn.chromium.org/blink/trunk@164243 bbb929c8-8fbe-4397-9dbb-9b2b20218538