Use /ToUnicode when extracting simple TrueType fonts without explicit encoding

DEVSIX-1681

Autoported commit.
Original commit hash: [d447044a1]

Author: Snipx

itext.tests/itext.kernel.tests/resources/itext/kernel/parser/HighlightItemsTest/cmp_ISO-TC171-SC2_N0896_SC2WG5_Edinburgh_Agenda.pdf

@@ -70,7 +70,8 @@ private DocTrueTypeFont(PdfDictionary fontDictionary)
             subtype = fontDictionary.GetAsName(PdfName.Subtype);
         }
 
-        internal static TrueTypeFont CreateFontProgram(PdfDictionary fontDictionary, FontEncoding fontEncoding) {
+        internal static TrueTypeFont CreateFontProgram(PdfDictionary fontDictionary, FontEncoding fontEncoding, CMapToUnicode
+             toUnicode) {
             iText.Kernel.Font.DocTrueTypeFont fontProgram = new iText.Kernel.Font.DocTrueTypeFont(fontDictionary);
             FillFontDescriptor(fontProgram, fontDictionary.GetAsDictionary(PdfName.FontDescriptor));
             PdfNumber firstCharNumber = fontDictionary.GetAsNumber(PdfName.FirstChar);
@@ -86,6 +87,11 @@ internal static TrueTypeFont CreateFontProgram(PdfDictionary fontDictionary, Fon
                 if (glyph.HasValidUnicode() && fontEncoding.ConvertToByte(glyph.GetUnicode()) == i) {
                     fontProgram.unicodeToGlyph.Put(glyph.GetUnicode(), glyph);
                 }
+                else {
+                    if (toUnicode != null) {
+                        glyph.SetChars(toUnicode.Lookup(i));
+                    }
+                }
                 if (widths[i] > 0) {
                     glyphsWithWidths++;
                     fontProgram.avgWidth += widths[i];

itext.tests/itext.kernel.tests/resources/itext/kernel/parser/HighlightItemsTest/cmp_ISO-TC171-SC2_N0896_SC2WG5_Edinburgh_Agenda_characters.pdf

@@ -80,7 +80,7 @@ internal PdfTrueTypeFont(PdfDictionary fontDictionary)
             newFont = false;
             CMapToUnicode toUni = FontUtil.ProcessToUnicode(fontDictionary.Get(PdfName.ToUnicode));
             fontEncoding = DocFontEncoding.CreateDocFontEncoding(fontDictionary.Get(PdfName.Encoding), toUni);
-            fontProgram = DocTrueTypeFont.CreateFontProgram(fontDictionary, fontEncoding);
+            fontProgram = DocTrueTypeFont.CreateFontProgram(fontDictionary, fontEncoding, toUni);
             embedded = ((IDocFontProgram)fontProgram).GetFontFile() != null;
             subset = false;
         }

itext/itext.kernel/itext/kernel/font/DocTrueTypeFont.cs

@@ -1 +1 @@
-76b261370b3e1689f7a7ec4eba6025f42ccacf03
+d447044a10cf9b74295cb6265d7959eda9830653