Rename DocumentMarkerController::RenderedRectsForMarkers()

Rename DocumentMarkerController::RenderedRectsForMarkers() to
RenderedRectsForTextMatchMarkers() and remove the marker_type param.
After https://codereview.chromium.org/2883503004, we only create
RenderedDocumentMarkers for TextMatch markers, and the type param is
no longer needed.

BUG=707867

Review-Url: https://codereview.chromium.org/2886893008
Cr-Commit-Position: refs/heads/master@{#473411}
4 files changed