Removing useless Win7 checks + standardize its use

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 <stddef.h>
 
 #include <iomanip>
@@ skipping 239 matching lines @@
     LOG(ERROR) << "Unable to delete printer";
     ClosePrinter(handle);
     return result;
   }
   ClosePrinter(handle);
   return S_OK;
 }
 
 bool IsOSSupported() {
   // We don't support Vista or older.
-  base::win::Version version = base::win::GetVersion();
-  return (version >= base::win::VERSION_WIN7);
+  return base::win::GetVersion() >= base::win::VERSION_WIN7;
 }
 
 HRESULT RegisterVirtualDriver(const base::FilePath& install_path) {
   HRESULT result = S_OK;
 
   DCHECK(base::DirectoryExists(install_path));
   if (!IsOSSupported()) {
     LOG(ERROR) << "Requires Windows 7 or later.";
     return HRESULT_FROM_WIN32(ERROR_OLD_WIN_VERSION);
   }
@@ skipping 153 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;
 }