Remove _FPDF_ByteStringFromHex as it is unused

core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp

Index: core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index 3057948959807b1e84e336729ad5ee6dc3efe3c2..e095414ffeb0e428dfd2a29207e5d3a9b6bff504 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -1532,42 +1532,3 @@ void CPDF_StreamContentParser::AddPathObject(int FillType, FX_BOOL bStroke) {
     m_pCurStates->m_ClipPath.AppendPath(Path, PathClipType, TRUE);
   }
 }
-CFX_ByteString _FPDF_ByteStringFromHex(CFX_BinaryBuf& src_buf) {
-  CFX_ByteTextBuf buf;
-  FX_BOOL bFirst = TRUE;
-  int code = 0;
-  const uint8_t* str = src_buf.GetBuffer();
-  FX_DWORD size = src_buf.GetSize();
-  for (FX_DWORD i = 0; i < size; i++) {
-    uint8_t ch = str[i];
-    if (ch >= '0' && ch <= '9') {
-      if (bFirst) {
-        code = (ch - '0') * 16;
-      } else {
-        code += ch - '0';
-        buf.AppendChar((char)code);
-      }
-      bFirst = !bFirst;
-    } else if (ch >= 'A' && ch <= 'F') {
-      if (bFirst) {
-        code = (ch - 'A' + 10) * 16;
-      } else {
-        code += ch - 'A' + 10;
-        buf.AppendChar((char)code);
-      }
-      bFirst = !bFirst;
-    } else if (ch >= 'a' && ch <= 'f') {
-      if (bFirst) {
-        code = (ch - 'a' + 10) * 16;
-      } else {
-        code += ch - 'a' + 10;
-        buf.AppendChar((char)code);
-      }
-      bFirst = !bFirst;
-    }
-  }
-  if (!bFirst) {
-    buf.AppendChar((char)code);
-  }
-  return buf.GetByteString();
-}