GitLab

 * Sync step documentation ('line position' -> 'line' and similar.)
 * Remove remnants of 'best position' and re-number steps.
 * Implement new cue dodging logic.

BUG=301580

Review URL: https://codereview.chromium.org/1306833003

git-svn-id: svn://svn.chromium.org/blink/trunk@200987 bbb929c8-8fbe-4397-9dbb-9b2b20218538