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

cloud_print/virtual_driver/win/install/setup.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 <windows.h>
 #include <setupapi.h>  // Must be included after windows.h
 #include <winspool.h>
 #include <iomanip>
 
 #include "base/at_exit.h"
@@ skipping 175 matching lines @@
 
 UINT CALLBACK CabinetCallback(PVOID data,
                               UINT notification,
                               UINT_PTR param1,
                               UINT_PTR param2) {
   const base::FilePath* temp_path(
       reinterpret_cast<const base::FilePath*>(data));
   if (notification == SPFILENOTIFY_FILEINCABINET) {
     FILE_IN_CABINET_INFO* info =
         reinterpret_cast<FILE_IN_CABINET_INFO*>(param1);
-    for (int i = 0; i < arraysize(kDependencyList); i++) {
+    for (size_t i = 0; i < arraysize(kDependencyList); i++) {
       base::FilePath base_name(info->NameInCabinet);
       base_name = base_name.BaseName();
       if (base::FilePath::CompareEqualIgnoreCase(base_name.value().c_str(),
                                                  kDependencyList[i])) {
         StringCchCopy(info->FullTargetName, MAX_PATH,
                       temp_path->Append(kDependencyList[i]).value().c_str());
         return FILEOP_DOIT;
       }
     }
     return FILEOP_SKIP;
@@ skipping 343 matching lines @@
 
   VLOG(0) << GetErrorMessage(retval)
           << " HRESULT=0x" << std::setbase(16) << retval;
 
   // Installer is silent by default as required by Google Update.
   if (base::CommandLine::ForCurrentProcess()->HasSwitch("verbose")) {
     DisplayWindowsMessage(NULL, retval, LoadLocalString(IDS_DRIVER_NAME));
   }
   return retval;
 }