Enable MSVC warning for unused locals.

chrome/installer/util/installer_state_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 <windows.h>
 
 #include <fstream>
 
 #include "base/base_paths.h"
 #include "base/command_line.h"
@@ skipping 356 matching lines @@
       Version found_version(*installer_state.GetCurrentVersion(machine_state));
       EXPECT_TRUE(found_version.IsValid());
       if (found_version.IsValid())
         EXPECT_TRUE(current_version.Equals(found_version));
     }
   }
 }
 
 TEST_F(InstallerStateTest, InstallerResult) {
   const bool system_level = true;
-  bool multi_install = false;
   HKEY root = system_level ? HKEY_LOCAL_MACHINE : HKEY_CURRENT_USER;
 
   RegKey key;
   std::wstring launch_cmd = L"hey diddle diddle";
   std::wstring value;
   DWORD dw_value;
 
   // check results for a fresh install of single Chrome
   {
     RegistryOverrideManager override_manager;
@@ skipping 429 matching lines @@
   // Critical update newer than the new version.
   EXPECT_FALSE(
       installer_state.DetermineCriticalVersion(NULL, *pv_version_).IsValid());
   EXPECT_FALSE(
       installer_state.DetermineCriticalVersion(opv_version_, *pv_version_)
           .IsValid());
   EXPECT_FALSE(
       installer_state.DetermineCriticalVersion(pv_version_, *pv_version_)
           .IsValid());
 }