Check for overflow in CMap_GetCode.

core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp

Index: core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
diff --git a/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp b/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
index ccf49ee46a3d290b1789d52943a721cfbcf072a1..9564a972e7610d0419c90a6e2420f42159e176dd 100644
--- a/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
+++ b/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
@@ -28,6 +28,10 @@ TEST(fpdf_font_cid, CMap_GetCode) {
   EXPECT_EQ(12u, CPDF_CMapParser::CMap_GetCode("12"));
   EXPECT_EQ(12u, CPDF_CMapParser::CMap_GetCode("12d"));
   EXPECT_EQ(128u, CPDF_CMapParser::CMap_GetCode("128"));
+
+  // Overflow a uint32_t.
+  EXPECT_EQ(0u, CPDF_CMapParser::CMap_GetCode("<FFFFFFFFa"));
+  EXPECT_EQ(4294967295u, CPDF_CMapParser::CMap_GetCode("<FFFFFFFF"));
 }
 
 TEST(fpdf_font_cid, CMap_GetCodeRange) {