Revert of base: Remove using:: declaration from version.h header.

chrome/installer/util/product_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/util/product_unittest.h"
 
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/test_reg_util_win.h"
@@ skipping 74 matching lines @@
     machine_state.Initialize();
     EXPECT_TRUE(machine_state.GetProductState(
         system_level, distribution->GetType()) == NULL);
 
     // Let's pretend chrome is installed.
     RegKey version_key(root, distribution->GetVersionKey().c_str(),
                        KEY_ALL_ACCESS);
     ASSERT_TRUE(version_key.Valid());
 
     const char kCurrentVersion[] = "1.2.3.4";
-    base::Version current_version(kCurrentVersion);
+    Version current_version(kCurrentVersion);
     version_key.WriteValue(google_update::kRegVersionField,
                            base::UTF8ToWide(
                                current_version.GetString()).c_str());
 
     // We started out with a non-msi product.
     machine_state.Initialize();
     const installer::ProductState* chrome_state =
         machine_state.GetProductState(system_level, distribution->GetType());
     EXPECT_TRUE(chrome_state != NULL);
     if (chrome_state != NULL) {
@@ skipping 16 matching lines @@
     if (chrome_state != NULL)
       EXPECT_TRUE(chrome_state->is_msi());
   }
 }
 
 TEST_F(ProductTest, LaunchChrome) {
   // TODO(tommi): Test Product::LaunchChrome and
   // Product::LaunchChromeAndWait.
   LOG(ERROR) << "Test not implemented.";
 }