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

third_party/WebKit/Source/core/layout/api/LineLayoutText.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 LineLayoutText_h
 #define LineLayoutText_h
 
 #include "core/layout/LayoutText.h"
 #include "core/layout/api/LineLayoutItem.h"
 #include "platform/LayoutUnit.h"
 #include "platform/text/TextPath.h"
 #include "wtf/Forward.h"
 
 namespace blink {
 
 class LayoutText;
 
 class LineLayoutText : public LineLayoutItem {
 public:
     explicit LineLayoutText(LayoutText* layoutObject) : LineLayoutItem(layoutObject) { }
 
     explicit LineLayoutText(const LineLayoutItem& item)
         : LineLayoutItem(item)
     {
         ASSERT(!item || item.isText());
     }
 
+    LineLayoutText(std::nullptr_t) : LineLayoutItem(nullptr) { }
+
     LineLayoutText() { }
 
     InlineTextBox* firstTextBox() const
     {
         return toText()->firstTextBox();
     }
 
     void extractTextBox(InlineTextBox* inlineTextBox)
     {
         toText()->extractTextBox(inlineTextBox);
@@ skipping 100 matching lines @@
     }
 
 private:
     LayoutText* toText() { return toLayoutText(layoutObject()); }
     const LayoutText* toText() const { return toLayoutText(layoutObject()); }
 };
 
 } // namespace blink
 
 #endif // LineLayoutText_h