[DMC #5] Add SpellCheckMarkerListImpl

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

Index: third_party/WebKit/Source/core/editing/markers/DocumentMarkerList.h
diff --git a/third_party/WebKit/Source/core/editing/markers/DocumentMarkerList.h b/third_party/WebKit/Source/core/editing/markers/DocumentMarkerList.h
index 0ec98740b7a903df0f465477a0d413361b4e3cf6..671a7ad7d4633b7334cd765be57e1dacb9e3feb4 100644
--- a/third_party/WebKit/Source/core/editing/markers/DocumentMarkerList.h
+++ b/third_party/WebKit/Source/core/editing/markers/DocumentMarkerList.h
@@ -37,12 +37,6 @@ class CORE_EXPORT DocumentMarkerList
   // Returns true if at least one marker is removed, false otherwise
   virtual bool RemoveMarkers(unsigned start_offset, int length) = 0;
 
-  // Returns true if a marker was removed, false otherwise.
-  // TODO(rlanday): remove this method from this interface once we have a
-  // Spelling/Grammar-specific marker list impl to put this on
-  virtual bool RemoveMarkersUnderWords(const String& node_text,

[yosin_UTC9, 2017/05/08 04:50:54]

Could you make this patch into two patches?
1. Introduce SpellinMarkerListImpl
2. Move AddMarkerAndMergeOverlapping()
3. Introduce type case (DEFINE_TYPE_CASTS) for DocumentMarkerList
4. Move RemoveMarkersUnderWords()

-                                       const Vector<String>& words) = 0;
-
   // Returns true if at least one marker is shifted or removed, false otherwise
   virtual bool ShiftMarkers(unsigned offset,
                             unsigned old_length,