[ActiveSuggestionMarker #1] Introduce abstract StyleableMarker subclass of DocumentMarker

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

Index: third_party/WebKit/Source/core/editing/markers/StyleableMarker.h
diff --git a/third_party/WebKit/Source/core/editing/markers/StyleableMarker.h b/third_party/WebKit/Source/core/editing/markers/StyleableMarker.h
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index 0000000000000000000000000000000000000000..6109234e45f73c7c9b17fd154af95764524f7416
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+++ b/third_party/WebKit/Source/core/editing/markers/StyleableMarker.h
@@ -0,0 +1,47 @@
+// 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 StyleableMarker_h
+#define StyleableMarker_h
+
+#include "core/editing/markers/DocumentMarker.h"
+
+namespace blink {
+
+// An abstract subclass of DocumentMarker to be subclassed by DocumentMarkers
+// that should be renderable with customizable formatting.
+class CORE_EXPORT StyleableMarker : public DocumentMarker {
+ public:
+  enum class Thickness { kThin, kThick };
+
+  StyleableMarker(unsigned start_offset,
+                  unsigned end_offset,
+                  Color underline_color,
+                  Thickness,
+                  Color background_color);
+
+  // StyleableMarker-specific
+  Color UnderlineColor() const;
+  bool IsThick() const;
+  Color BackgroundColor() const;
+
+ private:
+  const Color underline_color_;
+  const Color background_color_;
+  const Thickness thickness_;
+
+  DISALLOW_COPY_AND_ASSIGN(StyleableMarker);
+};
+
+bool CORE_EXPORT IsStyleableMarker(const DocumentMarker&);
+
+DEFINE_TYPE_CASTS(StyleableMarker,
+                  DocumentMarker,
+                  marker,
+                  IsStyleableMarker(*marker),
+                  IsStyleableMarker(marker));
+
+}  // namespace blink
+
+#endif