base: Remove unnecessary using declarations from values.h

chrome/browser/extensions/external_pref_extension_loader.cc

 // Copyright (c) 2011 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/browser/extensions/external_pref_extension_loader.h"
 
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "content/browser/browser_thread.h"
 #include "content/common/json_value_serializer.h"
 
 namespace {
 
 // Caller takes ownership of the returned dictionary.
 DictionaryValue* ExtractPrefs(const FilePath& path,
-                              ValueSerializer* serializer) {
+                              base::ValueSerializer* serializer) {
   std::string error_msg;
   Value* extensions = serializer->Deserialize(NULL, &error_msg);
   if (!extensions) {
     LOG(WARNING) << "Unable to deserialize json data: " << error_msg
                  << " In file " << path.value() << " .";
   } else {
     if (!extensions->IsType(Value::TYPE_DICTIONARY)) {
       LOG(WARNING) << "Expected a JSON dictionary in file "
                    << path.value() << " .";
     } else {
@@ skipping 80 matching lines @@
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   prefs_.reset(testing_prefs_->DeepCopy());
   LoadFinished();
 }
 
 ExternalTestingExtensionLoader::~ExternalTestingExtensionLoader() {}
 
 const FilePath ExternalTestingExtensionLoader::GetBaseCrxFilePath() {
   return fake_base_path_;
 }