base: Remove using declaration from test_suite.h header.

chrome/installer/util/run_all_unittests.cc

 // Copyright (c) 2006-2008 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/bind.h"
 #include "base/test/launcher/unit_test_launcher.h"
 #include "base/test/test_suite.h"
 #include "base/win/scoped_com_initializer.h"
 #include "chrome/common/chrome_paths.h"
 
 int main(int argc, char** argv) {
-  TestSuite test_suite(argc, argv);
+  base::TestSuite test_suite(argc, argv);
 
   // Register Chrome Path provider so that we can get test data dir.
   chrome::RegisterPathProvider();
 
   base::win::ScopedCOMInitializer com_initializer;
   if (!com_initializer.succeeded())
     return -1;
   return base::LaunchUnitTests(
       argc,
       argv,
       base::Bind(&base::TestSuite::Run, base::Unretained(&test_suite)));
 }