[DMC #24] Add SpellingMarker and GrammarMarker (subclasses of DocumentMarker)

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

Index: third_party/WebKit/Source/core/editing/markers/SpellingMarker.h
diff --git a/third_party/WebKit/Source/core/editing/markers/SpellingMarker.h b/third_party/WebKit/Source/core/editing/markers/SpellingMarker.h
new file mode 100644
index 0000000000000000000000000000000000000000..d4dac785b6f652a42ec73dab396515c30e18f92a
--- /dev/null
+++ b/third_party/WebKit/Source/core/editing/markers/SpellingMarker.h
@@ -0,0 +1,28 @@
+// 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 SpellingMarker_h
+#define SpellingMarker_h
+
+#include "core/editing/markers/SpellCheckMarker.h"
+
+namespace blink {
+
+// A subclass of DocumentMarker used to store information specific to spelling
+// markers. Spelling and grammar markers are identical except that they mark
+// either spelling or grammar errors, respectively, so nearly all functionality
+// is delegated to a common base class, SpellCheckMarker.
+class CORE_EXPORT SpellingMarker final : public SpellCheckMarker {
+ public:
+  SpellingMarker(unsigned start_offset,
+                 unsigned end_offset,
+                 const String& description);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SpellingMarker);
+};
+
+}  // namespace blink
+
+#endif