Add support using EXPECT_EQ with NullableString16 objects.

base/strings/nullable_string16_unittest.cc

+// Copyright 2013 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 "base/strings/nullable_string16.h"
+#include "base/strings/utf_string_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+TEST(NullableString16Test, DefaultConstructor) {
+  NullableString16 s;
+  EXPECT_TRUE(s.is_null());
+  EXPECT_EQ(string16(), s.string());
+}
+
+TEST(NullableString16Test, Equals) {
+  NullableString16 a(ASCIIToUTF16("hello"), false);
+  NullableString16 b(ASCIIToUTF16("hello"), false);
+  EXPECT_EQ(a, b);
+}
+
+TEST(NullableString16Test, NotEquals) {
+  NullableString16 a(ASCIIToUTF16("hello"), false);
+  NullableString16 b(ASCIIToUTF16("world"), false);
+  EXPECT_NE(a, b);
+}
+
+TEST(NullableString16Test, NotEqualsNull) {
+  NullableString16 a(ASCIIToUTF16("hello"), false);
+  NullableString16 b;
+  EXPECT_NE(a, b);
+}
+
+}  // namespace base