Add CompositionMarkerList in preparation for DocumentMarkerController refactor

third_party/WebKit/Source/core/editing/markers/EditingMarkerList.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/EditingMarkerList.h"
+
+#include <algorithm>
+#include "core/editing/markers/DocumentMarkerController.h"
+
+namespace blink {
+
+EditingMarkerList::EditingMarkerList() : m_markersAreSorted(true) {}
+
+bool EditingMarkerList::isEditingMarkerList() const {
+  return true;
+}
+
+void EditingMarkerList::push_back(DocumentMarker* marker) {
+  DCHECK(marker->type() == allowedMarkerType());
+  if (m_markersAreSorted && !m_markers.isEmpty() &&
+      m_markers.back()->endOffset() > marker->startOffset())
+    m_markersAreSorted = false;
+  m_markers.push_back(marker);
+}
+
+void EditingMarkerList::clear() {
+  m_markersAreSorted = true;
+  DocumentMarkerList::clear();
+}
+
+bool EditingMarkerList::markerListIsSorted() const {
+  return m_markersAreSorted;
+}
+
+DEFINE_TRACE(EditingMarkerList) {
+  visitor->trace(m_markers);
+  DocumentMarkerList::trace(visitor);
+}
+
+}  // namespace blink