[ActiveSuggestionMarker #1] Introduce abstract StyleableMarker subclass of DocumentMarker

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

+// 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.
+
+#include "core/editing/markers/StyleableMarker.h"
+
+namespace blink {
+
+StyleableMarker::StyleableMarker(unsigned start_offset,
+                                 unsigned end_offset,
+                                 Color underline_color,
+                                 Thickness thickness,
+                                 Color background_color)
+    : DocumentMarker(start_offset, end_offset),
+      underline_color_(underline_color),
+      background_color_(background_color),
+      thickness_(thickness) {}

[yosin_UTC9, 2017/06/06 01:18:15]

Q: Do we allow |underline_color == background_color|?
Is it better to have DCHECK_NE(underline_color, background_color)?

[rlanday, 2017/06/06 01:42:44]

I don't know that we'd ever actually need to have both colors set the same, but
I also don't see a strong reason why we should DCHECK() in this case. DCHECKing
feels like it would be surprising behavior. It also doesn't seem totally
unreasonable that we might at some point have a StyleableMarker class that a
caller might want to sometimes render with both colors set to transparent, to be
invisible.

+
+Color StyleableMarker::UnderlineColor() const {
+  return underline_color_;
+}
+
+bool StyleableMarker::IsThick() const {
+  return thickness_ == Thickness::kThick;
+}
+
+Color StyleableMarker::BackgroundColor() const {
+  return background_color_;
+}
+
+bool IsStyleableMarker(const DocumentMarker& marker) {
+  DocumentMarker::MarkerType type = marker.GetType();
+  return type == DocumentMarker::kComposition;
+}
+
+}  // namespace blink