[Sync] Move some things from driver to base.

components/sync/driver/system_encryptor_unittest.cc

-// Copyright 2014 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 "components/sync/driver/system_encryptor.h"
-
-#include "build/build_config.h"
-#include "components/os_crypt/os_crypt_mocker.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace syncer {
-
-namespace {
-
-const char kPlaintext[] = "The Magic Words are Squeamish Ossifrage";
-
-class SystemEncryptorTest : public testing::Test {
- protected:
-  SystemEncryptor encryptor_;
-};
-
-TEST_F(SystemEncryptorTest, EncryptDecrypt) {
-  // SystemEncryptor ends up needing access to the keychain on OS X,
-  // so use the mock keychain to prevent prompts.
-  ::OSCryptMocker::SetUpWithSingleton();
-  std::string ciphertext;
-  EXPECT_TRUE(encryptor_.EncryptString(kPlaintext, &ciphertext));
-  EXPECT_NE(kPlaintext, ciphertext);
-  std::string plaintext;
-  EXPECT_TRUE(encryptor_.DecryptString(ciphertext, &plaintext));
-  EXPECT_EQ(kPlaintext, plaintext);
-  ::OSCryptMocker::TearDown();
-}
-
-}  // namespace
-
-}  // namespace syncer