Simplify HexEncode.

base/string_util_unittest.cc

 // Copyright (c) 2006-2008 The Chromium 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 <math.h>
 #include <stdarg.h>
 
 #include <limits>
 #include <sstream>
 
@@ skipping 1437 matching lines @@
     std::wstring output;
     EXPECT_EQ(cases[i].result,
               ElideString(cases[i].input, cases[i].max_len, &output));
     EXPECT_TRUE(output == cases[i].output);
   }
 }
 
 TEST(StringUtilTest, HexEncode) {
   std::string hex(HexEncode(NULL, 0));
   EXPECT_EQ(hex.length(), 0U);
-  unsigned char bytes[] = {0x01, 0xff, 0x02, 0xfe, 0x03};
+  unsigned char bytes[] = {0x01, 0xff, 0x02, 0xfe, 0x03, 0x80, 0x81};
   hex = HexEncode(bytes, sizeof(bytes));
-  EXPECT_EQ(hex.compare("01FF02FE03"), 0);
+  EXPECT_EQ(hex.compare("01FF02FE038081"), 0);
 }