[Sync] Fixing easy lint violations.

components/sync_sessions/revisit/sessions_page_revisit_observer_unittest.cc

 // Copyright 2015 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_sessions/revisit/sessions_page_revisit_observer.h"
 
 #include <string>
+#include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "base/test/histogram_tester.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
 #include "components/sessions/core/serialized_navigation_entry_test_helper.h"
 #include "components/sessions/core/session_types.h"
 #include "components/sync_sessions/synced_session.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
@@ skipping 168 matching lines @@
   sessions.push_back(session1.get());
   sessions.push_back(session2.get());
   SessionsPageRevisitObserver observer(
       base::MakeUnique<TestForeignSessionsProvider>(sessions, true));
 
   base::HistogramTester histogram_tester;
   CheckAndExpect(&observer, GURL(kExampleUrl), true, true);
 }
 
 }  // namespace sync_sessions