Avoid style clobbering in setCompositionFromExistingText. (2nd land)

Source/core/editing/markers/DocumentMarker.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 78 matching lines @@
     return match ? trueInstance : falseInstance;
 }
 
 inline DocumentMarkerTextMatch* toDocumentMarkerTextMatch(DocumentMarkerDetails* details)
 {
     if (details && details->isTextMatch())
         return static_cast<DocumentMarkerTextMatch*>(details);
     return 0;
 }
 
+class TextCompositionMarkerDetails final : public DocumentMarkerDetails {
+public:
+    static PassRefPtrWillBeRawPtr<TextCompositionMarkerDetails> instanceFor(Color underlineColor, bool thick, Color backgroundColor);

[yosin_UTC9, 2015/09/08 06:34:05]

nit: Could you use |create()| instead of |instanceFor()|?
It seems only DocumentMarker uses |instanceFor()|. 
We'll rename |instanceFor()|.

+
+    bool isComposition() const override { return true; }
+    Color underlineColor() const { return m_underlineColor; }
+    bool thick() const { return m_thick; }
+    Color backgroundColor() const { return m_backgroundColor; }
+
+private:
+    TextCompositionMarkerDetails(Color underlineColor, bool thick, Color backgroundColor)
+        : m_underlineColor(underlineColor)
+        , m_thick(thick)
+        , m_backgroundColor(backgroundColor)
+    {
+    }
+
+    Color m_underlineColor;
+    bool m_thick;

[yosin_UTC9, 2015/09/08 06:34:05]

nit: Rather than having alignment padding in middle of object, it is better
to move |bool m_thick| to last of member variable declarations for
adding other |bool| in future.

+    Color m_backgroundColor;
+};
+
+PassRefPtrWillBeRawPtr<TextCompositionMarkerDetails> TextCompositionMarkerDetails::instanceFor(Color underlineColor, bool thick, Color backgroundColor)
+{
+    return adoptRefWillBeNoop(new TextCompositionMarkerDetails(underlineColor, thick, backgroundColor));
+}
+
+inline TextCompositionMarkerDetails* toTextCompositionMarkerDetails(DocumentMarkerDetails* details)
+{
+    if (details && details->isComposition())
+        return static_cast<TextCompositionMarkerDetails*>(details);
+    return nullptr;
+}
+
+
 DocumentMarker::DocumentMarker(MarkerType type, unsigned startOffset, unsigned endOffset, const String& description, uint32_t hash)
     : m_type(type)
     , m_startOffset(startOffset)
     , m_endOffset(endOffset)
     , m_details(description.isEmpty() ? nullptr : DocumentMarkerDescription::create(description))
     , m_hash(hash)
 {
 }
 
 DocumentMarker::DocumentMarker(unsigned startOffset, unsigned endOffset, bool activeMatch)
     : m_type(DocumentMarker::TextMatch)
     , m_startOffset(startOffset)
     , m_endOffset(endOffset)
     , m_details(DocumentMarkerTextMatch::instanceFor(activeMatch))
     , m_hash(0)
 {
 }
 
+DocumentMarker::DocumentMarker(unsigned startOffset, unsigned endOffset, Color underlineColor, bool thick, Color backgroundColor)
+    : m_type(DocumentMarker::Composition)
+    , m_startOffset(startOffset)
+    , m_endOffset(endOffset)
+    , m_details(TextCompositionMarkerDetails::instanceFor(underlineColor, thick, backgroundColor))
+    , m_hash(0)
+{
+}
+
 DocumentMarker::DocumentMarker(const DocumentMarker& marker)
     : m_type(marker.type())
     , m_startOffset(marker.startOffset())
     , m_endOffset(marker.endOffset())
     , m_details(marker.details())
     , m_hash(marker.hash())
 {
 }
 
 void DocumentMarker::shiftOffsets(int delta)
@@ skipping 14 matching lines @@
     return emptyString();
 }
 
 bool DocumentMarker::activeMatch() const
 {
     if (DocumentMarkerTextMatch* details = toDocumentMarkerTextMatch(m_details.get()))
         return details->activeMatch();
     return false;
 }
 
+Color DocumentMarker::underlineColor() const
+{
+    if (TextCompositionMarkerDetails* details = toTextCompositionMarkerDetails(m_details.get()))
+        return details->underlineColor();
+    return Color::transparent;
+}
+
+bool DocumentMarker::thick() const
+{
+    if (TextCompositionMarkerDetails* details = toTextCompositionMarkerDetails(m_details.get()))
+        return details->thick();
+    return false;
+}
+
+Color DocumentMarker::backgroundColor() const
+{
+    if (TextCompositionMarkerDetails* details = toTextCompositionMarkerDetails(m_details.get()))
+        return details->backgroundColor();
+    return Color::transparent;
+}
+
 DEFINE_TRACE(DocumentMarker)
 {
     visitor->trace(m_details);
 }
 
 } // namespace blink