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

third_party/WebKit/Source/core/layout/api/LineLayoutBoxModel.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 LineLayoutBoxModel_h
 #define LineLayoutBoxModel_h
 
 #include "core/layout/LayoutBoxModelObject.h"
 #include "core/layout/api/LineLayoutItem.h"
 #include "platform/LayoutUnit.h"
 
 namespace blink {
 
 class LayoutBoxModelObject;
 
 class LineLayoutBoxModel : public LineLayoutItem {
 public:
     explicit LineLayoutBoxModel(LayoutBoxModelObject* layoutBox)
         : LineLayoutItem(layoutBox)
     {
     }
 
     explicit LineLayoutBoxModel(const LineLayoutItem& item)
         : LineLayoutItem(item)
     {
         ASSERT(!item || item.isBoxModelObject());
     }
 
+    LineLayoutBoxModel(std::nullptr_t) : LineLayoutItem(nullptr) { }
+
     LineLayoutBoxModel() { }
 
     PaintLayer* layer() const
     {
         return toBoxModel()->layer();
     }
 
     LayoutUnit lineHeight(bool firstLine, LineDirectionMode lineDirectionMode, LinePositionMode linePositionMode = PositionOnContainingLine) const
     {
         return toBoxModel()->lineHeight(firstLine, lineDirectionMode, linePositionMode);
@@ skipping 150 matching lines @@
 };
 
 inline LineLayoutBoxModel LineLayoutItem::enclosingBoxModelObject() const
 {
     return LineLayoutBoxModel(layoutObject()->enclosingBoxModelObject());
 }
 
 } // namespace blink
 
 #endif // LineLayoutBoxModel_h