[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 {
 
 // A subclass of DocumentMarker used to implement functionality shared between
 // spelling and grammar markers. These two marker types both store a
 // description string that can contain suggested replacements for a misspelling
 // or grammar error.
 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 { return description_; }
 
  private:
   const String description_;
 
   DISALLOW_COPY_AND_ASSIGN(SpellCheckMarker);
 };
 
 bool CORE_EXPORT IsSpellCheckMarker(const DocumentMarker&);
 
 DEFINE_TYPE_CASTS(SpellCheckMarker,
                   DocumentMarker,
                   marker,
                   IsSpellCheckMarker(*marker),
                   IsSpellCheckMarker(marker));
 
 }  // namespace blink
 
 #endif