Move Extension into extensions namespace

chrome/common/extensions/feature_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/common/extensions/feature.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 using chrome::VersionInfo;
+using extensions::Extension;
 using extensions::Feature;
 
 namespace {
 
 struct IsAvailableTestData {
   std::string extension_id;
   Extension::Type extension_type;
   Feature::Location location;
   Feature::Platform platform;
   int manifest_version;
@@ skipping 522 matching lines @@
       IsAvailableInChannel("", VersionInfo::CHANNEL_CANARY));
   EXPECT_EQ(Feature::UNSUPPORTED_CHANNEL,
       IsAvailableInChannel("", VersionInfo::CHANNEL_DEV));
   EXPECT_EQ(Feature::UNSUPPORTED_CHANNEL,
       IsAvailableInChannel("", VersionInfo::CHANNEL_BETA));
   EXPECT_EQ(Feature::UNSUPPORTED_CHANNEL,
       IsAvailableInChannel("", VersionInfo::CHANNEL_STABLE));
 }
 
 }  // namespace