[Line Layout API] Convert AbstractInlineTextBox to new line layout API

third_party/WebKit/Source/core/layout/api/LineLayoutRubyRun.h

 // Copyright 2015 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 LineLayoutRubyRun_h
 #define LineLayoutRubyRun_h
 
 #include "core/layout/LayoutRubyRun.h"
 #include "core/layout/api/LineLayoutBlockFlow.h"
 
 namespace blink {
 
 class LineLayoutRubyRun : public LineLayoutBlockFlow {
 public:
     explicit LineLayoutRubyRun(LayoutRubyRun* layoutRubyRun)
         : LineLayoutBlockFlow(layoutRubyRun)
     {
     }
 
     explicit LineLayoutRubyRun(const LineLayoutItem& item)
         : LineLayoutBlockFlow(item)
     {
         ASSERT(!item || item.isRubyRun());
     }
 
+    LineLayoutRubyRun(std::nullptr_t) : LineLayoutBlockFlow(nullptr) { }
+
     LineLayoutRubyRun() { }
 
     void getOverhang(bool firstLine, LineLayoutItem startLayoutItem, LineLayoutItem endLayoutItem, int& startOverhang, int& endOverhang) const
     {
         toRubyRun()->getOverhang(firstLine, startLayoutItem, endLayoutItem, startOverhang, endOverhang);
     }
 
     LayoutRubyText* rubyText() const
     {
         return toRubyRun()->rubyText();
@@ skipping 12 matching lines @@
 
     const LayoutRubyRun* toRubyRun() const
     {
         return toLayoutRubyRun(layoutObject());
     }
 };
 
 } // namespace blink
 
 #endif // LineLayoutRubyRun_h