[Sync] Fixing sync_driver lint violations and adding PRESUBMIT lint check.

components/sync_driver/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 "components/sync_driver/backup_rollback_controller.h"
 
+#include <string>
+
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "components/sync_driver/signin_manager_wrapper.h"
 #include "components/sync_driver/sync_driver_switches.h"
 #include "components/sync_driver/sync_prefs.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 119 matching lines @@
   EXPECT_FALSE(controller_->StartRollback());
   EXPECT_EQ(0, fake_prefs_.GetRemainingRollbackTries());
 
   PumpLoop();
   EXPECT_FALSE(rollback_started_);
 }
 
 #endif
 
 }  // anonymous namespace