Reland of clang/win: Enable -Wunused-value completely.

chrome/installer/setup/setup_util_unittest.cc

 // Copyright (c) 2012 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 "chrome/installer/setup/setup_util_unittest.h"
 
 #include <windows.h>
 
 #include <string>
 
@@ skipping 599 matching lines @@
   }
 
   ASSERT_TRUE(RegKey(root_, path_.c_str(), KEY_WRITE).Valid());
   DeleteRegistryKeyPartial(root_, path_.c_str(), to_preserve_);
   ASSERT_TRUE(RegKey(root_, path_.c_str(), KEY_READ).Valid());
 
   // Ensure that the preserved subkeys are still present.
   {
     base::win::RegistryKeyIterator it(root_, path_.c_str());
     ASSERT_EQ(to_preserve_.size(), it.SubkeyCount());
-    for (it; it.Valid(); ++it) {
+    for (; it.Valid(); ++it) {
       ASSERT_NE(to_preserve_.end(),
                 std::find_if(to_preserve_.begin(), to_preserve_.end(),
                              [&it](const base::string16& key_name) {
                                return base::ToLowerASCII(it.Name()) ==
                                       base::ToLowerASCII(key_name);
                              }))
           << it.Name();
     }
   }
 
   // Ensure that all values are absent.
   {
     base::win::RegistryValueIterator it(root_, path_.c_str());
     ASSERT_EQ(0, it.ValueCount());
   }
 }
 
 }  // namespace installer