[Android WebView] Cleanup after r157538

In r157538, a temporary code was introduced which has become
redundant after r223027 landed in Chromium. Cleaning up.

BUG=288037
R=abarth@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23694032

git-svn-id: svn://svn.chromium.org/blink/trunk@157764 bbb929c8-8fbe-4397-9dbb-9b2b20218538