Refactor DocumentMarkerController::RemoveMarkers(const MarkerRemoverPredicate&)

MarkerRemoverPredicate seems to have been added with some amount of generality
in mind, but the way it's written it only serves a single purpose, so I'm
refactoring the RemoveMarkers() method that takes it to just take a vector of
words instead.

BUG=707867

Review-Url: https://codereview.chromium.org/2833753004
Cr-Commit-Position: refs/heads/master@{#466516}
3 files changed