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

third_party/WebKit/Source/core/editing/markers/SpellCheckMarker.h

 // 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.
 
 #ifndef SpellCheckMarker_h
 #define SpellCheckMarker_h
 
 #include "core/editing/markers/DocumentMarker.h"
 
 namespace blink {
 
 class CORE_EXPORT SpellCheckMarker : public DocumentMarker {
  public:
-  SpellCheckMarker(DocumentMarker::MarkerType,
-                   unsigned start_offset,
+  SpellCheckMarker(unsigned start_offset,
                    unsigned end_offset,
                    const String& description);
 
   const String& Description() const;
 
  private:
   String description_;
 };
 
 DEFINE_TYPE_CASTS(SpellCheckMarker,
                   DocumentMarker,
                   marker,
                   marker->GetType() == DocumentMarker::kSpelling ||
                       marker->GetType() == DocumentMarker::kGrammar,
                   marker.GetType() == DocumentMarker::kSpelling ||
                       marker.GetType() == DocumentMarker::kGrammar);
 
 }  // namespace blink
 
 #endif