Add PDFCharIsLineEnding helper

core/include/fpdfapi/fpdf_parser.h

Index: core/include/fpdfapi/fpdf_parser.h
diff --git a/core/include/fpdfapi/fpdf_parser.h b/core/include/fpdfapi/fpdf_parser.h
index d121bb4f79485c2f05b924e750229d436b17f87b..32509eb837a7766cbab2248e9a77bd2b5093c146 100644
--- a/core/include/fpdfapi/fpdf_parser.h
+++ b/core/include/fpdfapi/fpdf_parser.h
@@ -61,6 +61,10 @@ inline bool PDFCharIsOther(uint8_t c) {
   return PDF_CharType[c] == 'R';
 }
 
+inline bool PDFCharIsLineEnding(uint8_t c) {
+  return c == '\r' || c == '\n';
+}
+
 // Indexed by 8-bit char code, contains unicode code points.
 extern const FX_WORD PDFDocEncoding[256];