Apparently we weren't running this unittest....

base/string16_unittest.cc

 // Copyright (c) 2009 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 <sstream>
 
 #include "base/string16.h"
 #include "base/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 25 matching lines @@
     surrogate_pair.push_back(0xdf00);
     surrogate_pair.push_back('z');
 
     // Will get converted to the invalid char + 's': EF BF BD 's'.
     string16 unterminated_surrogate;
     unterminated_surrogate.push_back(0xd800);
     unterminated_surrogate.push_back('s');
 
     std::ostringstream stream;
     stream << initial_surrogate << "," << final_surrogate << ","
-           << surrogate_pair << ",", unterminated_surrogate;
+           << surrogate_pair << "," << unterminated_surrogate;
 
     EXPECT_STREQ("\xef\xbf\xbd,\xef\xbf\xbd,\xf0\x90\x8c\x80z,\xef\xbf\xbds",
                  stream.str().c_str());
   }
 }
 
 #endif