Define a single macro for enabling backup function.

chrome/browser/sync/backup_rollback_controller_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 "chrome/browser/sync/backup_rollback_controller.h"
 
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/sync/managed_user_signin_manager_wrapper.h"
 #include "chrome/common/chrome_switches.h"
 #include "components/sync_driver/sync_prefs.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using ::testing::Return;
 
 namespace {
 
-#if defined(OS_WIN) || defined(OS_MACOSX) || (defined(OS_LINUX) && !defined(OS_CHROMEOS))
+#if defined(ENABLE_PRE_SYNC_BACKUP)
 
 class MockSigninManagerWrapper : public ManagedUserSigninManagerWrapper {
  public:
   MockSigninManagerWrapper() : ManagedUserSigninManagerWrapper(NULL, NULL) {}
 
   MOCK_CONST_METHOD0(GetEffectiveUsername, std::string());
 };
 
 class FakeSyncPrefs : public sync_driver::SyncPrefs {
  public:
@@ skipping 154 matching lines @@
   controller_->OnRollbackReceived();
   controller_->Start(base::TimeDelta());
   EXPECT_TRUE(backup_started_);
   EXPECT_FALSE(rollback_started_);
 }
 
 #endif
 
 }  // anonymous namespace