Respect ToUnicode map when it maps a charcode to unicode 0

fpdfsdk/fpdftext_embeddertest.cpp

 // Copyright 2015 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.
 
 #include "core/fxcrt/include/fx_basic.h"
 #include "public/fpdf_text.h"
 #include "public/fpdfview.h"
 #include "testing/embedder_test.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/test_support.h"
@@ skipping 370 matching lines @@
                                         16, 16, 16, 16, 16, 16, 16, 16, 16, 16};
 
   int count = FPDFText_CountChars(textpage);
   ASSERT_EQ(FX_ArraySize(kExpectedFontsSizes), static_cast<size_t>(count));
   for (int i = 0; i < count; ++i)
     EXPECT_EQ(kExpectedFontsSizes[i], FPDFText_GetFontSize(textpage, i)) << i;
 
   FPDFText_ClosePage(textpage);
   UnloadPage(page);
 }
+
+TEST_F(FPDFTextEmbeddertest, ToUnicode) {
+  EXPECT_TRUE(OpenDocument("bug_583.pdf"));
+  FPDF_PAGE page = LoadPage(0);
+  EXPECT_TRUE(page);
+
+  FPDF_TEXTPAGE textpage = FPDFText_LoadPage(page);
+  EXPECT_TRUE(textpage);
+
+  ASSERT_EQ(1, FPDFText_CountChars(textpage));
+  EXPECT_EQ(static_cast<unsigned int>(0), FPDFText_GetUnicode(textpage, 0));
+
+  FPDFText_ClosePage(textpage);
+  UnloadPage(page);
+}