Fixup incorrect include guards.

core/src/fxcodec/jbig2/JBig2_Segment.h

 // 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 _JBIG2_SEGMENT_H_
-#define _JBIG2_SEGMENT_H_
+#ifndef CORE_SRC_FXCODEC_JBIG2_JBIG2_SEGMENT_H_
+#define CORE_SRC_FXCODEC_JBIG2_JBIG2_SEGMENT_H_
 
 #include "core/src/fxcodec/jbig2/JBig2_Define.h"
 #include "core/src/fxcodec/jbig2/JBig2_HuffmanTable.h"
 #include "core/src/fxcodec/jbig2/JBig2_PatternDict.h"
 #include "core/src/fxcodec/jbig2/JBig2_SymbolDict.h"
 
 #define JBIG2_GET_INT32(buf) \
   (((buf)[0] << 24) | ((buf)[1] << 16) | ((buf)[2] << 8) | (buf)[3])
 #define JBIG2_GET_INT16(buf) (((buf)[0] << 8) | (buf)[1])
 typedef enum {
@@ skipping 36 matching lines @@
   JBig2_SegmentState m_State;
   JBig2_ResultType m_nResultType;
   union {
     CJBig2_SymbolDict* sd;
     CJBig2_PatternDict* pd;
     CJBig2_Image* im;
     CJBig2_HuffmanTable* ht;
     void* vd;
   } m_Result;
 };
-#endif
+
+#endif  // CORE_SRC_FXCODEC_JBIG2_JBIG2_SEGMENT_H_