[DMC #25] Make DocumentMarker::GetType() virtual

third_party/WebKit/Source/core/editing/markers/CompositionMarker.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/CompositionMarker.h"
 
 namespace blink {
 
 CompositionMarker::CompositionMarker(unsigned start_offset,
                                      unsigned end_offset,
                                      Color underline_color,
                                      bool thick,
                                      Color background_color)
-    : DocumentMarker(DocumentMarker::kComposition, start_offset, end_offset),
+    : DocumentMarker(start_offset, end_offset),
       underline_color_(underline_color),
       background_color_(background_color),
       thick_(thick) {}
 
+DocumentMarker::MarkerType CompositionMarker::GetType() const {
+  return DocumentMarker::kComposition;
+}
+
 Color CompositionMarker::UnderlineColor() const {
   return underline_color_;
 }
 
 bool CompositionMarker::Thick() const {
   return thick_;
 }
 
 Color CompositionMarker::BackgroundColor() const {
   return background_color_;
 }
 
 }  // namespace blink