Add TextMatchMarkerListImpl::SetTextMatchMarkersActive()

Adding this helper method allows us to simplify the implementation of
DocumentMarkerController::SetTextMatchMarkersActive(), which was previously
depending on details of the implementation of TextMatchMarkerListImpl (whether
or not it stores its markers in sorted order).

BUG=707867

Review-Url: https://codereview.chromium.org/2904973003
Cr-Commit-Position: refs/heads/master@{#474914}
3 files changed