Fix missing or broken include guard macros in pdfium headers.

This has no ill-effect at present, but may be distracting when viewing the file
since it just looks wrong.

R=jun_fang@foxitsoftware.com

Review URL: https://codereview.chromium.org/461933003

core/include/fpdfdoc/fpdf_ap.h

diff --git a/core/include/fpdfdoc/fpdf_ap.h b/core/include/fpdfdoc/fpdf_ap.h
index c2299fc..78f9676 100644
--- a/core/include/fpdfdoc/fpdf_ap.h
+++ b/core/include/fpdfdoc/fpdf_ap.h
@@ -4,7 +4,9 @@
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
+#ifndef _FPDF_AP_H_
 #define _FPDF_AP_H_
+
 #include "../fxcrt/fx_basic.h"
 #include "../fpdfapi/fpdf_parser.h"
 #include "fpdf_vt.h"
@@ -90,3 +92,5 @@
 
     static CFX_ByteString					GenerateColorAP(const CPVT_Color & color, const FX_BOOL & bFillOrStroke);
 };
+
+#endif  // _FPDF_AP_H_

core/src/fpdfapi/fpdf_page/pageint.h

diff --git a/core/src/fpdfapi/fpdf_page/pageint.h b/core/src/fpdfapi/fpdf_page/pageint.h
index 4e097ca..52aded0 100644
--- a/core/src/fpdfapi/fpdf_page/pageint.h
+++ b/core/src/fpdfapi/fpdf_page/pageint.h
@@ -4,6 +4,9 @@
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
+#ifndef _PAGEINT_H_
+#define _PAGEINT_H_
+
 #include "../../../include/fpdfapi/fpdf_pageobj.h"
 #define PARSE_STEP_LIMIT		100
 #define STREAM_PARSE_BUFSIZE	20480
@@ -503,3 +506,5 @@
 protected:
     CFX_MapByteStringToPtr	m_NamingCache;
 };
+
+#endif  // _PAGEINT_H_

core/src/fpdfdoc/pdf_vt.h

diff --git a/core/src/fpdfdoc/pdf_vt.h b/core/src/fpdfdoc/pdf_vt.h
index 09ed0b0..8fc9c7c 100644
--- a/core/src/fpdfdoc/pdf_vt.h
+++ b/core/src/fpdfdoc/pdf_vt.h
@@ -4,7 +4,9 @@
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
+#ifndef _PDF_VT_H_
 #define _PDF_VT_H_
+
 class CPVT_Size;
 class CPVT_FloatRect;
 struct CPVT_SectionInfo;
@@ -637,3 +639,5 @@
     CPVT_WordPlace							m_CurPos;
     CPDF_VariableText *						m_pVT;
 };
+
+#endif  // _PDF_VT_H_

core/src/fxge/dib/dib_int.h

diff --git a/core/src/fxge/dib/dib_int.h b/core/src/fxge/dib/dib_int.h
index 1e6d82e..19dc358 100644
--- a/core/src/fxge/dib/dib_int.h
+++ b/core/src/fxge/dib/dib_int.h
@@ -1,9 +1,12 @@
 // 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 _DIB_INT_H_
+#define _DIB_INT_H_
+
 class CPDF_FixedMatrix : public CFX_Object
 {
 public:
@@ -86,3 +89,5 @@
     void	StretchVert();
     int		m_State;
 };
+
+#endif  // _DIB_INT_H_

core/src/fxge/ge/text_int.h

diff --git a/core/src/fxge/ge/text_int.h b/core/src/fxge/ge/text_int.h
index a3c9417..c8d5596 100644
--- a/core/src/fxge/ge/text_int.h
+++ b/core/src/fxge/ge/text_int.h
@@ -4,6 +4,9 @@
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
+#ifndef _TEXT_INT_H_
+#define _TEXT_INT_H_
+
 struct _CFX_UniqueKeyGen {
     void		Generate(int count, ...);
     FX_CHAR		m_Key[128];
@@ -98,3 +101,5 @@
     int					m_PitchFamily;
     CFX_ByteString		m_FontTables;
 };
+
+#endif  // _TEXT_INT_H_

fpdfsdk/include/formfiller/FFL_Utils.h

diff --git a/fpdfsdk/include/formfiller/FFL_Utils.h b/fpdfsdk/include/formfiller/FFL_Utils.h
index 2fdc7b1..4b77aa2 100644
--- a/fpdfsdk/include/formfiller/FFL_Utils.h
+++ b/fpdfsdk/include/formfiller/FFL_Utils.h
@@ -4,6 +4,9 @@
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
+#ifndef _FFL_UTILS_H_
+#define _FFL_UTILS_H_
+
 #define FFL_BASE_USERUNIT			1.0f / 72.0f
 
 template<class T> T FFL_MIN (const T & i, const T & j) { return ((i < j) ? i : j); }
@@ -18,3 +21,4 @@
 	static FX_BOOL					TraceObject(CPDF_Object* pObj);
 };
 
+#endif  // _FFL_UTILS_H_