DocumentMarkerList refactor as an interface

third_party/WebKit/Source/core/editing/markers/DocumentMarkerList.cpp

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/editing/markers/DocumentMarkerList.h"
+
+namespace blink {
+
+DocumentMarkerList::DocumentMarkerList() {}
+
+DocumentMarkerList::~DocumentMarkerList() {}
+
+bool DocumentMarkerList::isCompositionMarkerList() const {
+  return false;
+}
+
+bool DocumentMarkerList::isSpellCheckMarkerList() const {
+  return false;
+}
+
+bool DocumentMarkerList::isTextMatchMarkerList() const {
+  return false;
+}
+
+}  // namespace blink