Move Extension into extensions namespace

chrome/common/extensions/manifest_tests/extension_manifests_old_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/manifest_tests/extension_manifest_test.h"
 
 #include "chrome/common/extensions/extension.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 // Tests that the old permission name "unlimited_storage" still works for
 // backwards compatibility (we renamed it to "unlimitedStorage").
 TEST_F(ExtensionManifestTest, OldUnlimitedStoragePermission) {
-  scoped_refptr<Extension> extension = LoadAndExpectSuccess(
+  scoped_refptr<extensions::Extension> extension = LoadAndExpectSuccess(
       "old_unlimited_storage.json",
-      Extension::INTERNAL,
-      Extension::STRICT_ERROR_CHECKS);
+      extensions::Extension::INTERNAL,
+      extensions::Extension::STRICT_ERROR_CHECKS);
   EXPECT_TRUE(extension->HasAPIPermission(
       ExtensionAPIPermission::kUnlimitedStorage));
 }