[LayoutNG] Add NGInlineBreakToken and back of NGInlineLayoutAlgorithm

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

+// Copyright 2017 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 NGInlineBreakToken_h
+#define NGInlineBreakToken_h
+
+#include "core/CoreExport.h"
+#include "core/layout/ng/ng_break_token.h"
+
+namespace blink {
+
+class NGInlineNode;
+
+// Represents a break token for an inline node.
+class CORE_EXPORT NGInlineBreakToken : public NGBreakToken {
+ public:
+  // Creates a break token for a node which did fragment, and can potentially
+  // produce more fragments.
+  static RefPtr<NGInlineBreakToken> create(NGInlineNode* node,
+                                           unsigned item_index,
+                                           unsigned text_offset) {
+    return adoptRef(new NGInlineBreakToken(node, item_index, text_offset));
+  }
+
+  // Creates a break token for a node which cannot produce any more fragments.
+  static RefPtr<NGInlineBreakToken> create(NGLayoutInputNode* node) {
+    return adoptRef(new NGInlineBreakToken(node));
+  }
+
+  unsigned ItemIndex() const { return item_index_; }
+  unsigned TextOffset() const { return text_offset_; }
+
+ private:
+  NGInlineBreakToken(NGInlineNode* node,
+                     unsigned item_index,
+                     unsigned text_offset);
+
+  explicit NGInlineBreakToken(NGLayoutInputNode* node);
+
+  unsigned item_index_;
+  unsigned text_offset_;
+};
+
+DEFINE_TYPE_CASTS(NGInlineBreakToken,
+                  NGBreakToken,
+                  token,
+                  token->Type() == NGBreakToken::kInlineBreakToken,
+                  token.Type() == NGBreakToken::kInlineBreakToken);
+
+}  // namespace blink
+
+#endif  // NGInlineBreakToken_h