Update StringPrintfTest.Invalid for VS 2015

base/strings/stringprintf_unittest.cc

Index: base/strings/stringprintf_unittest.cc
diff --git a/base/strings/stringprintf_unittest.cc b/base/strings/stringprintf_unittest.cc
index c49637c23f256fe321414576c9b6a4eaac45136c..e0b320fe452c8368cbd6d956f43c4051bce9a5c6 100644
--- a/base/strings/stringprintf_unittest.cc
+++ b/base/strings/stringprintf_unittest.cc
@@ -148,10 +148,10 @@ TEST(StringPrintfTest, GrowBoundary) {
   EXPECT_STREQ(src, out.c_str());
 }
 
-// TODO(evanm): what's the proper cross-platform test here?
 #if defined(OS_WIN)
-// sprintf in Visual Studio fails when given U+FFFF. This tests that the
-// failure case is gracefuly handled.
+// vswprintf in Visual Studio 2013 fails when given U+FFFF. This tests that the
+// failure case is gracefuly handled. In Visual Studio 2015 the bad character
+// is passed through.
 TEST(StringPrintfTest, Invalid) {
   wchar_t invalid[2];
   invalid[0] = 0xffff;
@@ -159,7 +159,11 @@ TEST(StringPrintfTest, Invalid) {
 
   std::wstring out;
   SStringPrintf(&out, L"%ls", invalid);
+#if _MSC_VER >= 1900
+  EXPECT_STREQ(invalid, out.c_str());
+#else
   EXPECT_STREQ(L"", out.c_str());
+#endif
 }
 #endif