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

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

 /*
  * This file is part of the DOM implementation for WebCore.
  *
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 115 matching lines @@
    public:
     MisspellingMarkers() : MarkerTypes(kSpelling | kGrammar) {}
   };
 
   DocumentMarker(MarkerType,
                  unsigned start_offset,
                  unsigned end_offset,
                  const String& description);
   virtual ~DocumentMarker();
 
-  MarkerType GetType() const { return type_; }
+  virtual MarkerType GetType() const = 0;
   unsigned StartOffset() const { return start_offset_; }
   unsigned EndOffset() const { return end_offset_; }
 
   struct MarkerOffsets {
     unsigned start_offset;
     unsigned end_offset;
   };
 
   Optional<MarkerOffsets> ComputeOffsetsAfterShift(unsigned offset,
                                                    unsigned old_length,
                                                    unsigned new_length) const;
 
   // Offset modifications are done by DocumentMarkerController.
   // Other classes should not call following setters.
   void SetStartOffset(unsigned offset) { start_offset_ = offset; }
   void SetEndOffset(unsigned offset) { end_offset_ = offset; }
   void ShiftOffsets(int delta);
 
   DEFINE_INLINE_VIRTUAL_TRACE() {}
 
  protected:
-  DocumentMarker(MarkerType, unsigned start_offset, unsigned end_offset);
+  DocumentMarker(unsigned start_offset, unsigned end_offset);
 
  private:
-  MarkerType type_;
   unsigned start_offset_;
   unsigned end_offset_;
 
   DISALLOW_COPY_AND_ASSIGN(DocumentMarker);
 };
 
 using DocumentMarkerVector = HeapVector<Member<DocumentMarker>>;
 
 }  // namespace blink
 
 #endif  // DocumentMarker_h