clang/win: Let some chromium_code targets build with -Wextra.

base/test/test_reg_util_win_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/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/test_reg_util_win.h"
 #include "base/time/time.h"
@@ skipping 71 matching lines @@
   create_key.Close();
 
   AssertKeyExists(kTestKeyPath);
 
   DWORD value;
   base::win::RegKey read_key;
   EXPECT_EQ(ERROR_SUCCESS,
             read_key.Open(HKEY_CURRENT_USER, kTestKeyPath, KEY_READ));
   EXPECT_TRUE(read_key.Valid());
   EXPECT_EQ(ERROR_SUCCESS, read_key.ReadValueDW(kTestValueName, &value));
-  EXPECT_EQ(42, value);
+  EXPECT_EQ(42u, value);
   read_key.Close();
 
   manager_.reset();
 
   AssertKeyAbsent(kTestKeyPath);
 }
 
 TEST_F(RegistryOverrideManagerTest, DeleteStaleKeys) {
   base::Time::Exploded kTestTimeExploded = {2013, 11, 1, 4, 0, 0, 0, 0};
   base::Time kTestTime = base::Time::FromUTCExploded(kTestTimeExploded);
@@ skipping 18 matching lines @@
   manager_.reset();
 
   AssertKeyAbsent(path_garbage);
   AssertKeyAbsent(path_very_stale);
   AssertKeyAbsent(path_stale);
   AssertKeyExists(path_current);
   AssertKeyExists(path_future);
 }
 
 }  // namespace registry_util