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

third_party/WebKit/Source/core/layout/api/LineLayoutInline.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 LineLayoutInline_h
 #define LineLayoutInline_h
 
 #include "core/layout/LayoutInline.h"
 #include "core/layout/api/LineLayoutBoxModel.h"
 #include "platform/LayoutUnit.h"
@@ skipping 10 matching lines @@
         : LineLayoutBoxModel(layoutInline)
     {
     }
 
     explicit LineLayoutInline(const LineLayoutItem& item)
         : LineLayoutBoxModel(item)
     {
         ASSERT(!item || item.isLayoutInline());
     }
 
+    LineLayoutInline(std::nullptr_t) : LineLayoutBoxModel(nullptr) { }
+
     LineLayoutInline() { }
 
     LineLayoutItem firstChild() const
     {
         return LineLayoutItem(toInline()->firstChild());
     }
 
     LineLayoutItem lastChild() const
     {
         return LineLayoutItem(toInline()->lastChild());
@@ skipping 53 matching lines @@
     const LayoutInline* toInline() const
     {
         return toLayoutInline(layoutObject());
     }
 
 };
 
 } // namespace blink
 
 #endif // LineLayoutInline_h