[LayoutNG] Introduce NGPhysicalFragment and make NGFragment a 'view'

third_party/WebKit/Source/core/layout/ng/ng_physical_text_fragment.h

+// Copyright 2016 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 NGPhysicalTextFragment_h
+#define NGPhysicalTextFragment_h
+
+#include "core/CoreExport.h"
+#include "core/layout/ng/ng_physical_fragment_base.h"
+#include "core/layout/ng/ng_layout_input_text.h"
+#include "platform/LayoutUnit.h"
+#include "platform/heap/Handle.h"
+#include "wtf/text/WTFString.h"
+
+namespace blink {
+
+class CORE_EXPORT NGPhysicalTextFragment final : public NGPhysicalFragmentBase {
+ public:
+  NGPhysicalTextFragment(NGPhysicalSize size, NGPhysicalSize overflow)
+      : NGPhysicalFragmentBase(size, overflow, FragmentText) {}
+
+  String Text() const { return text_list_->Text(start_offset_, end_offset_); }
+
+  DEFINE_INLINE_TRACE_AFTER_DISPATCH() {
+    visitor->trace(text_list_);
+    NGPhysicalFragmentBase::traceAfterDispatch(visitor);
+  }
+
+ private:
+  Member<NGLayoutInputText> text_list_;
+  unsigned start_offset_;
+  unsigned end_offset_;
+};
+
+DEFINE_TYPE_CASTS(NGPhysicalTextFragment,
+                  NGPhysicalFragmentBase,
+                  text,
+                  text->Type() == NGPhysicalFragmentBase::FragmentText,
+                  text.Type() == NGPhysicalFragmentBase::FragmentText);
+
+}  // namespace blink
+
+#endif  // NGPhysicalTextFragment_h