Clean up DocumentMarker/DocumentMarkerController API
DMC refactor part 2
Follow-up to the first part of the refactor in
https://codereview.chromium.org/2723663002
- Rename some DocumentMarkerController methods to reflect that they only apply
to TextMatch markers
- Remove MarkerRemoverPredicate, now the method for removing spelling markers based on a list of words just takes a list of words
BUG=
707867