chromium 31.0.1650.48 compile error

In file included from ../../base/strings/safe_sprintf_unittest.cc:5:
../../base/strings/safe_sprintf.h:207:39: error: conversion from 'nullptr_t' to 'const internal::Arg' is ambiguous
  const internal::Arg arg_array[] = { args... };
                                      ^~~~
../../base/strings/safe_sprintf_unittest.cc:736:16: note: in instantiation of function template specialization 'base::strings::SafeSPrintf<40, nullptr_t>' requested here
  EXPECT_EQ(1, SafeSPrintf(buf, "%d", NULL));
               ^
../../testing/gtest/include/gtest/gtest.h:1930:33: note: expanded from macro 'EXPECT_EQ'
                      expected, actual)
                                ^
../../testing/gtest/include/gtest/gtest_pred_impl.h:162:40: note: expanded from macro 'EXPECT_PRED_FORMAT2'
  GTEST_PRED_FORMAT2_(pred_format, v1, v2, GTEST_NONFATAL_FAILURE_)
                                       ^
../../testing/gtest/include/gtest/gtest_pred_impl.h:147:43: note: expanded from macro 'GTEST_PRED_FORMAT2_'
  GTEST_ASSERT_(pred_format(#v1, #v2, v1, v2), \
                                          ^
../../testing/gtest/include/gtest/gtest_pred_impl.h:77:52: note: expanded from macro 'GTEST_ASSERT_'
  if (const ::testing::AssertionResult gtest_ar = (expression)) \
                                                   ^
../../base/strings/safe_sprintf.h:156:3: note: candidate constructor
  Arg(const char* s) : str(s), type(STRING) { }
  ^
../../base/strings/safe_sprintf.h:157:3: note: candidate constructor
  Arg(char* s)       : str(s), type(STRING) { }
  ^
1 error generated.
[1426/10153] CXX obj/base/strings/base_unittests.string16_unittest.o
ninja: build stopped: subcommand failed.