Revert of Remove the document tagged code as it is unused.

core/fpdfdoc/include/fpdf_tagged.h

Index: core/fpdfdoc/include/fpdf_tagged.h
diff --git a/core/fpdfdoc/include/fpdf_tagged.h b/core/fpdfdoc/include/fpdf_tagged.h
new file mode 100644
index 0000000000000000000000000000000000000000..43d69e8db92585622961d5d5400a1856714b2314
--- /dev/null
+++ b/core/fpdfdoc/include/fpdf_tagged.h
@@ -0,0 +1,93 @@
+// Copyright 2014 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#ifndef CORE_FPDFDOC_INCLUDE_FPDF_TAGGED_H_
+#define CORE_FPDFDOC_INCLUDE_FPDF_TAGGED_H_
+
+#include "core/fxge/include/fx_dib.h"
+
+class CPDF_Dictionary;
+class CPDF_Document;
+class IPDF_StructElement;
+
+class IPDF_StructTree {
+ public:
+  static IPDF_StructTree* LoadDoc(const CPDF_Document* pDoc);
+  static IPDF_StructTree* LoadPage(const CPDF_Document* pDoc,
+                                   const CPDF_Dictionary* pPageDict);
+
+  virtual ~IPDF_StructTree() {}
+
+  virtual int CountTopElements() const = 0;
+  virtual IPDF_StructElement* GetTopElement(int i) const = 0;
+};
+
+struct CPDF_StructKid {
+  enum { Invalid, Element, PageContent, StreamContent, Object } m_Type;
+
+  union {
+    struct {
+      IPDF_StructElement* m_pElement;
+      CPDF_Dictionary* m_pDict;
+    } m_Element;
+    struct {
+      uint32_t m_PageObjNum;
+      uint32_t m_ContentId;
+    } m_PageContent;
+    struct {
+      uint32_t m_PageObjNum;
+      uint32_t m_ContentId;
+      uint32_t m_RefObjNum;
+    } m_StreamContent;
+    struct {
+      uint32_t m_PageObjNum;
+      uint32_t m_RefObjNum;
+    } m_Object;
+  };
+};
+
+class IPDF_StructElement {
+ public:
+  virtual ~IPDF_StructElement() {}
+
+  virtual IPDF_StructTree* GetTree() const = 0;
+  virtual const CFX_ByteString& GetType() const = 0;
+  virtual IPDF_StructElement* GetParent() const = 0;
+  virtual CPDF_Dictionary* GetDict() const = 0;
+  virtual int CountKids() const = 0;
+  virtual const CPDF_StructKid& GetKid(int index) const = 0;
+
+  virtual CPDF_Object* GetAttr(const CFX_ByteStringC& owner,
+                               const CFX_ByteStringC& name,
+                               FX_BOOL bInheritable = FALSE,
+                               FX_FLOAT fLevel = 0.0F) = 0;
+
+  virtual CFX_ByteString GetName(const CFX_ByteStringC& owner,
+                                 const CFX_ByteStringC& name,
+                                 const CFX_ByteStringC& default_value,
+                                 FX_BOOL bInheritable = FALSE,
+                                 int subindex = -1) = 0;
+
+  virtual FX_ARGB GetColor(const CFX_ByteStringC& owner,
+                           const CFX_ByteStringC& name,
+                           FX_ARGB default_value,
+                           FX_BOOL bInheritable = FALSE,
+                           int subindex = -1) = 0;
+
+  virtual FX_FLOAT GetNumber(const CFX_ByteStringC& owner,
+                             const CFX_ByteStringC& name,
+                             FX_FLOAT default_value,
+                             FX_BOOL bInheritable = FALSE,
+                             int subindex = -1) = 0;
+
+  virtual int GetInteger(const CFX_ByteStringC& owner,
+                         const CFX_ByteStringC& name,
+                         int default_value,
+                         FX_BOOL bInheritable = FALSE,
+                         int subindex = -1) = 0;
+};
+
+#endif  // CORE_FPDFDOC_INCLUDE_FPDF_TAGGED_H_